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U. S. DEPARTMENT OF AGRICULTURE 

BUREAU OF SOILS 
MILTON WHITNEY, Chief 



Instructions to Field Parties 




WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1914 



U. S. DEPARTMENT OF AGRICULTURE 

BUREAU OF SOILS 

MILTON WHITNEY, Chief 



Instructions to Field Parties 







WASHINGTON 

GOVERNMENT PRINTING OFFICE 

1914 






■J. OF D, 
SEP 14 (914 



CONTENTS. 

V 

^ Page. 

Administration 5 

Organization of the Soil Survey 5 

Purpose of a soil survey 5 

General duties of field men 6 

Duties of inspectors — ' 9 

Field parties 13 

Plan and organization of field work 15 

(Correspondence and weekly report 16 

Soil samples and type specifications 16 

Care of instruments 28 

Accounts , 28 

Leave of absence 28 

Field outfit. 28 

Base maps 31 

Making a base map 32 

Features to be shown on map 57 

Identifying and mapping soils 67 

Examination of the soil material 68 

Topography and physiographic situation 80 

Source and derivation of material 80 

Agencies through which material has accumulated 82 

Elements of soil classification 83 

Mapping soils 85 

Instructions for estimating and mapping alkali 89 

Electrolytic determination of total salts 89 

Alkali maps 101 

Determination of total salts in water 107 

Care of electrolytic bridge 109 

Qualitative determination of alkali salts Ill 

Collection of laboratory samples of alkali soils, crusts, 

and waters 113 

Form of a soil survey report 113 

Appendix 121 

Value of agricultural products of the United States 121 

3 



LLUSTRATIONS 



Page. 
Fig. 1. Lines of equal magnetic declination and equal an- 
nual change Frontispiece. 

2. Odometer 33 

3. Chain scale 35 

4. Manner of recording traverse notes 39 

5 . Planetable top 41 

6. Planetable set up 42 

7. Alidade 43 

8. Planetable stations in road traverse 44 

9. Diagram illustrating location of points by intersec- 

tion during })rogress of road traverse 45 

10. Illustrating method of traversing railroads 46 

11. Compass 47 

12. Protractor 48 

13. Army sketching case 49 

14. Showing large number of stations necessary in 

traverse work 50 

15. Diagrams showing good and poor traverse 53 

10. Land lines jjlotted from description in tax receipt. . 54 

17. Illustrating detection of error in locating point by 

intersection, as a result of an incorrect odometer 

reading 55 

18. Showing method of procedure in running circuits 

where a base line has already been traversed 56 

19. Incorrect method of carrying traverse from one sheet 

to another 58 

20. Correct method of carrying traverse from one sheet 

to another 59 

21. Soil auger 69 

22. Geologist's hammer 70 

4 



INSTRUCTIONS TO FIELD PARTIES. 



ADMINISTRATION. 

Organization of the Soil Survey. 

The Soil Survey is a division of the Bureau of Soils. The organi- 
zation consists of a scientist in charge, inspectors in charge of 
inspection districts, State soil advisers, soil specialists, and a 
corps of field men, consisting of surveyors in charge of field parties 
and their assistants. 

The corps of field men constitutes the main body of the Survey's 
staff. The work of these men is both fundamental and practical, 
and the whole organization exists for the purpose of unifying and 
making public the facts that they accumulate and the relationships 
which they point out. 

The State soil advisers are Soil Survey officers assigned to the 
States for the purpose of interpreting the soil survey results to the 
men engaged in the various lines of agricultural investigation and 
demonstration in the State. 

Soil specialists are Survey officers engaged in the study of special 
soil problems, such as the relation of soils to special crop distribu- 
tion and the question of crop adaptation, so far as this is influenced 
by the character of the soil. 

The Purpose of a Soil Survey. 

The purpose of a soil survey is to map, classify, and correlate 
soils, to determine and describe their field characteristics, to 
report on the actual use being made of the soils and on their 
adaptation to various crops, so far as can be determined, and upon 
the relative productiveness of the several soil types. 

The field man should have a clear idea of the real value of the 
work he is doing and of its relation to the great industries of the 
country. In the gradual evolution of agricultural work the basic 

5 



INSTIUJCTIOAS TO FIEIJ) rAKTIES. 

nature of the \vork of the Soil Survey has come to be recognized. It 
is acknowledged that its primary function is to accumulate and 
make available knowledge concerning the soil, the soil's relation to 
crops, and the actual agricultural conditions obtaining on the 
soils of the country. 

This knowledge is valuable to many classes of peoi)le, most of 
whom can be grouped under four heads: 

1. Scientific men engaged in the investigation of problems re- 
lating to plant production, to farm management, to farm demon- 
stration, to stock raising, to problems of rural organization, to road 
])uilding, in short, to many of the branches of agricultural science. 

2. The farmer. 

8. Colonists, colonizing agencies, investors, development organi- 
zations, and individuals. 

4. Students of geographic, social, and economic sciences, with- 
out reference to agricultural industries. 

The Soil Survey is recognized as a scientific institution engaged 
in the accumTilation of data bearing upon the soil and its relation 
to agriculture. The Soil Survey field man is a scientist and his 
results are important and his methods are scientific, as much so 
in his x:)aiticular field as those of other scientists in their special 
lines of endeavor, whether working in the field, office, or labora- 
tory. His methods are not the same as those of the laboratory 
man but his results are just as reliable when he has used his meth- 
ods just as effectively. He is or should be not merely a getter 
of facts, but an interpreter of those facts. He must show relation- 
ships if he meq,sures up to the oj^portunities afforded him. He 
has the opportunity to study soils and agricultural facts and re- 
lationships in a more intimate way than has ever been permitted 
to any one in this or any other country. No other scientific man 
has ever studied the actual soil and agricultural conditions of any 
country as clcsely and in as much detail as does the Soil Survey 
fiekl man. 

General Duties of Field Men. 

Personal relation to State and department men.— It is expected that 
the Soil Survey staff will work in close relation with the depart- 
ment ofiicers and cooperating State officials. The success of this 



GENERAL DUTIES OF FIELD MEN. 7 

cooperative work will depend to a very great extent upon the field 
men, who will be in closer touch with the cooperating officers than 
anyone else in the bureau. This makes it imperative that the con- 
duct of the field men should be such as to win the respect of these 
officers. Men associated with the bureau men in the field either 
representing the State or other bureaus of the Government should 
be treated with courtesy and consideration. The administrative 
officers in the States should be visited when convenient and an atti- 
tude of hearty cooperation should be shown in all our relations with 
them. For the maintenance of proper cooperative relations the 
Soil Survey men should familiarize themselves with the regulations 
of the cooperating organizations. Any misunderstanding of meth- 
ods or criticism of the personnel of the cooperating forces where 
adjustment of such differences or misunderstandings can not be 
readily and amicably made by frank explanation should be taken 
up by correspondence with the chief of the bureau. The older men 
should exert every effort to train newly appointed assistants in the 
details of soil surveying with such care as will make them capable 
men, ready to take hold of the work with enthusiasm and conscien- 
tiousness. In no case should the new appointee be looked upon 
by the more experienced man as being valuable merely as a driver. 
The man in charge is expected to start such a recruit upon the 
actual performance of work the first time in the field, either in soil 
work or with the plane table. If the assistant proves capable he can 
soon be put to work alone, and thus made a valuable member of the 
party. On the other hand, should he not develop proper enthusi- 
asm, energy, and capacity after persistent and conscientious in- 
struction, the fact should be reported to the office and to the 
inspector. 

Personal conduct of the field men.- — In personal conduct, also, the 
bureau employee is expected to act in a way that will command 
the respect of the best element in the community where he happens 
to be at work. Public approval of the work and general acceptance 
of the results depend to a great extent on this, and the considera- 
tion of this fact should direct the personal conduct of the field man. 
He is the representative in the community of an important govern- 
mental organization and should earnestly endeavor to win respect 
by his personal conduct for the work in which he is engaged. 



8 INSTRUCTIONS TO FIELD PARTIES. 

This will be secured not througli any effort to push the 
claims of his work at all times or before all people, but rather by 
such attention to his daily work as will show the people with whom 
he comes in contact that he is a believer in the value of the work 
liimself . Strict attention to the work wins respect for both the man 
and the work. 

Relations to the ;ja6Zic.— Courteous treatment of the })ublic is re- 
(juired of every member of the force at all times. In answer to 
sori ;us inquiries the purpose of the Soil Survey should be explrined. 
It will not generally be necessary to go into such length)^ discussion 
as will interfere with the field work, since the essential features of 
soil surveying and the main purpose of the work can be briefly 
expl ined to those who are genuinely interested w^ithout loss of 
much time. Objections to entr.mce to the fields and hnds on the 
part of owners, renters, and managers can usually be satisfactorily 
overcome by explanation of the work and its public nature, with 
the statement that no damage will be done to crops cr property. 
It is best to secure permission from the proper authorities before 
entering upon lands to which the public generally is not admitted. 
In grazing regions where large areas are fenced permission should be 
secured for crossing the fences either by writing or interviewing the 
owners or managers. Staples pulled in letting down wire fences 
should invariably be carefully replaced, or the rails laid down in 
crossing rail fences should be replaced, and all gates closed. 

Information to the press.— Usually a news item in regard to the 
survey of a county or area in the local papers will serve as an expla- 
nation of the work. In a newspaper statement of this kind it is 
necessary merely to give the names of the members of the party 
and to describe briefly the kind of map to be made and the value 
of such a map. Lengthy newspaper or magazine articles must have 
the approval of the chief of the bureau before being submitted for 
publication. 

Information to cooperating officials. — During the progress of the 
work or at any other time the field man should furnish to any 
responsible cooperating official any information that may be asked 
concerning the progress of the survey work in the State or area 
with which the official is concerned, or anv other information 



INSTRUCTIONS TO FIELD PARTIES. 9 

relating to the work, it being understood that such information is 
for the official as an official and is not to be published or given out 
to the public in any other way. For other information reference 
should be made to the bureau. 

Duties of Inspectors. 

First inspection. — It is the duty of the inspector to visit each 
area surveyed in his division, usually twice, first to show the men 
in charge of an area what soil differences to map and to decide upon 
the textural and series name of the various soils. To accomplish 
this it is necessary for the inspector, in company with the man in 
charge of the party, to drive or walk over representative portions 
of the area and to make careful examinations of all the soils or at 
least all that can be seen on well-planned trips. Descriptions of 
the various soil types and phases should be recorded, from repre- 
sentative borings, in the field note book, by both the inspector 
and man in charge of the local area. At the completion of the 
inspection a report on form No. 65 should be submitted to the office. 

Second inspection. — A second trip should be made to each area 
as near the completion of a survey as possible. On this trip the 
inspector should see all the soils and phases that have been mapped, 
taking such additional notes as may be necessary for the prepara- 
tion of a comprehensive correlation memorandum. The character 
of mapping, the accuracy of traverse work, and of the delineation 
of soil boundaries should be carefully investigated, so that any 
necessary revision may be taken up with the field man upon the 
completion of the inspection. The field sheets should be examined 
to see that they join properly; that junction points of roads, streams, 
and soil boundaries can be understood by the draftsmen at the 
office; that each soil area, however small, is properly labeled with 
a symbol; that a complete legend is given on at least one of the 
field sheets; that such a legend corresponds in every detail with 
the symbols used on the map and that it includes every pencil 
number, letter symbol, or other symbol having any connection with 
the soils; that the name of the area and scale of the map are written 
on the back of each field sheet; that a line of magnetic north and 
south with the words "magnetic north" be placed on the front of 



10 INSTRUCTIONS TO FIELD PARTIES. 

each sheet; and that a diagram showing by means of the sheet 
numbers the proper arrangement of the field sheets be drawn on 
the back of at least one sheet. 

Preparation of correlation memorandum. ~K final correlation 
memorandum should be prepared by the inspector before leaving 
the area. This should include such descriptions of each type 
and phase based upon field examination of the soils as will enable 
the suggested correlations and classifications to be checked by the 
con-elation committee. In case the man in charge has not had 
much experience in writing soil survey reports, it is advisable to 
prepare the memorandum descriptions carefully, particularly the 
descriptions representing the typical development of the soils 
and their phases, so that such descriptions can be used by the 
field man in the preparation of his report. A copy of such a 
memorandum should be left with the man in charge, in case there 
is not sufficient time to have a typewritten copy returned from the 
office before the report is begun. 

Reading manuscript reports. — On returning to the office the 
inspector is required to read the manuscript of the report on each 
area assigned to him for inspection before the report is submitted 
to the editor of the bureau, for the purpose of making such revi- 
sion, corrections, or additions based upon his personal knowledge 
of the soils and conditions of the area as may. in his judgment be 
required to insure accuracy in the presentation of the actual 
field conditions. After revising the manuscript a final correlation 
memorandum, including all added suggestions pertaining to the 
soils of each area, should be prepared for the committee on soil 
correlation. The galley proof of the report, which will be furnished 
the inspector as soon as published, should be carefully read by 
the inspector in order to correct possible errors. 

Other duties. — The inspector should keep in touch with the 
reports of progress from the field parties in his division. In addi- 
tion he w411 render such other services in connection with the work 
of the bureau as may be required. It is the duty of the inspector 
to call attention to any particularly meritorious work on the part 
of the field man which may justify consideration in questions of 
promotion. He should also report to the bureau any irregularities 



DUTIES OF INSPECTORS. 11 

connected with the work of the soil survey parties within his 
division that may come to his attention, whether connected with 
soil mapping, with the preparation of a report, or the personal 
conduct of the men. 

Before leaving the area the inspector should fill out the following 
form and mail to this office: 

Form of inspection report. 
Form No. 65. 

Report of Inspection. 

Area: State: 

Estimated size of area square miles. 

Work started 

Surveyed to date square miles. 

Average rate per week square miles. 

Is the rate of progress satisfactory? 

Is the progress delayed hy — 

(a) Long drives? 

(&) Failure to recognize main soil distinctions instead of subordinate 
phases? 

Have you given any instructions looking to a more rapid progress of the 
work, and what? 

Is the party maintaining complete notes in field notebook, and are same 
up to date? (Instruct field men to send in field notebooks with reports 
and maps immediately upon completion of the area.) 

Are the soil boundaries and traverse work on base map legible and uni- 
formly indicated by proper symbols? 

Do the symbols on base map correspond to the symbols and names in legend 
and in' the report? 

Are points of juncture of roads, streams, etc., so indicated on the traverse 
sheets at the edges that they can be properly understood and joined in 
the office? 

What scale is being used on the map, and is it shown? 



Are the proper cultural and hydrographic symbols being used, and is the 
magnetic north and south shown on the base map? 

Is the area covered by the Land Office survey, and is each traverse sircuit 
properly tied to land lines, corners, or other points of kno^oi location? 

Is proper attention being given to the connecting of the work with previ- 
ously surveyed adjoining areas? 



Is a tracing or. copy of the map being made, and are precautions being taken 
to insure the safety of the map? 

Have you checked up the soil boundaries in the field in a sufficient number 
of cases to see that the field mapping is substantially correct? 



12 INSTKUCTIONS TO FIELD PARTIES. 



lave descriptions of all soils been sent in to the ofTce? 



Are unnecessary samples being taken for analyses to determine texture? 
(Two samples should be sufficient for any type if carefully selected.) 

Has the preparation of the report been started? What progress has been 
made? 

When do you think the area will be finished and the report completed and 
transmitted to the ofTice? 

Impress upon the field men that they should strive to have their maps and 
records legible and correct, with nothing obscure, so as to avoid all chance of error 
in office compilation and delay in preparation through the necessity of referring 
doubtful questions to the field". Make it clear also that the cost of the field work 
should be kept as low as is consistent with good progress and reasonable comfort. 

A list of soils with suggested correlations acconij^anies this report. 

Reached area Left 

liace Signature 



Inspector. 
Area: State: 

List of soils with suggested correlations. Those checked have been personally 
examined by me. 

Field name. Suggested correlation. 



Soil correlation. — In the correlation and classification of soils the 
recommendations of the inspectors, who are familiar with the soils 
over wide regions and who will examine in the field all types and 
phases, will be given the most careful consideration in the final 
decision. Any change that may later appear to be advisable will 
be taken up with the party chief of the area in question, in order 
that he may submit a statement of his ideas in favor of or against 
such proposed changes, and these statements will be given full con- 
sideration before the final recommendations are submitted to the 
chief of the bureau for his approval or disapproval. Also any 
changes proposed which do not coincide with the inspector's recom- 
mendations will be taken up with the inspector, in order that he too 
shall have the opportunity to submit a statement of his ideas as to 
Ihe advisability of such changes. In case of a series change pro- 
l)osed on the basis of soil samples submitted to the office, it will 
usually b(^ the practice to send a small tube of the soil material of 
a questionable sample to the field man and to the inspector if he is 



INSTRUCTIONS TO FIELD PARTIES. 13 

not in the office, so that errors rising from incorrect tagging or other 
sources will be eliminated if possible by a reinspection of the 
material. 

Field Parties. 

A field party in the detailed soil survey consists of two or more soil 
scientists, one of whom is assigned in charge. The assistant may or 
may not rank below the man in charge of a party. A certain amount 
of rotation is practiced in the assignment of men so that a man as- 
signed to a field party as chief one year may be assigned as assistant 
another year. This shifting of responsibility tends to furnish 
opportunity to the younger men of the staff. While this is in 
general a policy of the office, no man is assigned as chief of a party 
until he has shown the ability to do the work and write the report. 

The man in charge of any survey is responsible for the rate of 
progress and accuracy of the field work of the entire party, for the 
preparation of the report and maps, and for the carrying on of all 
necessary correspondence. The assistant performs such official 
duties as may be required of him by the man in charge. All mem- 
bers of a party should enter into the work with the will to help one 
another in every possible way, in order that the work may be 
carried forward at a good rate of progress and along lines leading to 
the construction of an accurate map and the wiiting of a good report. 
Each member of the party sTiould keep in touch with the latest 
correlations presented in the publications of the bureau, such as Bul- 
letin No. 96, and identify all soils occurringin the area. He should 
not, however, lose valuable time in attempting to correlate all the 
soils in his area when he finds such correlation difficult. A full and 
accurate description of a soil by the field man is much more impor- 
tant than is its field correlation . 

In company with the inspector the man in charge should examine 
all the soils of the area and take such notes as the inspector takes. 
He should map those soils and phases pointed out by the inspector 
and also make any revision advised by the inspector. In case a 
type seen during the inspection is not subsequently found in im- 
portant areas the field man should report that such a type was 
dropped on account of its small extent. The names approved by 
the inspector as the field names for the several soil types and phases 



14 INSTRUCTIONS TO FIELD PARTIES. 

should be consistently used thereafter on all soil samples, in the 
legend of the field sheets and tracing, and in the report. 

On rainy days the field men should work on their field sheets, the 
tracing copy required of the field sheets of all areas, prepare material 
for the report, and secure information regarding the agricultural 
practices of the area and other data needed in connection with the 
report. 

Where the assistant is a new man he should in all cases work with 
the head of the party until he has become sufficiently efficient in 
traverse work and soil mapping to take up the work of mapping 
alone. 

In carrying on the survey the work should be planned to avoid 
driving or walking over roads that have already been surveyed. 
Usually it is best not to carry the mapping more than 6 miles from 
headquarters, since work done at greater distances consumes much 
time in going and coming. This can be avoided by changing field 
headquarters and by stopping over one or more nights with farmers 
or at hotels situated close to the work. In working separately it is 
necessary to divide the area so that there will be no duplication of 
mapping. The man in charge, however, should from time to time 
look over the work of the assistant or assistants in order to maintain 
uniformity and to familiarize himself with the character of the work 
and the soils of the whole area. 

Most of the mapping of detail areas is done by means of horse and 
buggy, an odometer attached to the wheel being used to measure 
distances. Where necessary boats and camping oulfits should be 
secured to facilitate the work of the survey. In all cases a definite 
understanding as to charges should be reached with liverymen and 
the hirer of boats or other means of conveyance before final arrange- 
ments are made. It is advisable to inquire as to the peculiarities 
of horses, particularly to learn if there be any tendency toward colic, 
and to ascertain what to feed when stopping away from the barn. 
It is also a good plan to carry a supply of colic medicine, axle grease, 
a buggy wrench, wire, and necessary tools for making temporary 
repairs to vehicle or harness. It is usually possible to secure lower 
rates from liverymen where an outfit is to be used for a week or 
more. Such low rates should be secured by the man in charge 
whenever possible. 



TNSTRITOTIONS TO FIELD PARTIES. 15 

Plan and Organization of Field Work. 

The field work of the survey is planned in such a way that most 
of the work during the summer season is carried on in the northern 
part of the country and in the winter season in the southern part. 
The size of the field party placed in an area is determined largely 
by the necessity arising from this arrangement of completing 
projects of survey work within a season so that there will be as little 
suspended work on account of seasonal transfer of parties as possible. 

The number of men in each party, the individuals who shall 
compose it, and the man who will be placed in charge of the party 
are determined at headquarters, with the approval of the chief of the 
bureau . A letter of assignment is sent to each member of the party, 
the letter stating who will be in charge. Before the transfer can 
take place each member must have a letter of authorization, giving 
him authority to travel at Government expense. 

When the party has reached the area to be surveyed the chief of 
the party assumes charge and proceeds to organize the work. His 
work includes the making of a soil map of the area, the study of 
the distribution of crops and types of agriculture, the study of the 
soils, their crop adaptations, and relative productiveness. His 
most important work is the making of the soil map. The soil 
mapping can be done only by placing on a base map certain lines 
showing soil boundaries and certain colors or conventional symbols 
(pencil numbers, letters, or both) to represent the existence, in the 
areas delineated, of certain soils. 

Whenever possible a good base map will be furnished the chief of 
the field party upon his arrival in an area. This map should show 
streams, roads, railways, houses, churches, cities, and villages, 
township and section lines, and other permanently located objects, 
either natural or cultural. Where available, topographic maps will 
be furnished. Unfortunately, such a base map can not always be 
obtained. The area of country in the United States where this is 
possible is relatively small as yet and a considerable part of it covers 
mountainous regions, where detailed soil surveys are not frequently 
made. 

Where no reliable base map exists the field man must construct 
one. In the former case his whole attention can be directed to the 



16 INSTRUCTIONS TO FIELD PARTIES. 

soil mapping; in the latter case he must give attention to both base 
map making and soil mapping, either constructing the base map of 
an area and later doing his soil mapping or taking both up together 
and carrying them along at the same time. 

The unit area of the soil survey is usually a county, some other 
unit being adopted in special cases and for special reasons only. 

Correspondence and Weekly Report. 

All correspondence with the bureau should be addressed to 
the chief of the bureau. At least once each week the head of 
the party should report to the chief by letter, informing him of 
the progress of the work and the results accomplished, describing 
the new types of soil, and giving a statement of the health of the 
members of the party. In addition, the weekly itinerary report 
(Form 140) must be filled out and returned to this office. The 
weekly itinerary reports must be on file covering every day upon 
which the employee is absent from headquarters in Washington, 
but are not to be considered as taking the place of the weekly 
letters. 

Correspondence is filed in the office by areas and all correspond- 
ence should show the area number. Separate letters should, 
tlierefore, be written in regard to matters pertaining to different 
areas. Often letters are written that do not have a bearing upon 
any particular area, and such letters should also be written sep- 
arately from letters relating to an area. 

The bureau should be kept informed of the address of all the 
(ield men at all times, whether they are in the area to which they 
have been assigned, temporarily absent, or on leave of absence. 
( )rdinarily this may be accomplished through the use of Form 140, 
but when absolutely necessary the telegraph may be used. 

Soil Samples and Type Specifications. 

Great care should be exercised in the collection of soil samples 
in order that they may truly represent the types. The samples 
at least of the well-established types should be collected during 
the progress of the field work r?.ther than be postponed until the 
completion of the survey when, on account ol" the lack of time 



SOIL SAMPLES AND TYPE SPECIFICATIONS. 17 

or unfavorable weather conditions, it is frequently impossible to 
collect carefully selected, thoroughly representative samples. 

The field names of types and phases agreed upon between the 
inspector and field man should subsequently be adhered to rigidly. 
Any suggestion by the field man as to correlation should be made 
in a memorandum accompanying the report. Caution should be 
exercised that the office be kept fully informed as to any sub- 
sequent changes in the soil name in those areas that have not 
been inspected, either through correlation with an established 
type or alteration in the series or class name. Confusion will be 
avoided if, in subsequent correspondence, either the old or original 
name be given in parenthesis after the new or substituted name, or 
only the original name be used until completion of the area, when 
a list showing all changes in names of soil types can be submitted 
with the report upon the area. 

A soil to be correlated with a type must conform to it in certain 
broad, general features, but may differ from it in some details 
which do not greatly affect the crop value. The descriptions of 
the soil types given in Bulletin No. 96 must be taken as the defi- 
nition of the general average of the type; and it must be remem- 
bered that certain minor variations or phases may occur in different 
areas. 

In the selection of local names for new or doubtful types the 
series or apparent series relationship should be expressed — that is, 
soils which belong in the same series or are considered by the 
field man as belonging in the same series should be given the 
same series name. For example, soils found in a river bottom 
which differ only in texture should be classed in the same series. 
The same local or series name should not be employed for soils of 
different texture when no series relationship exists between them . 

Samples for laboratory examination. — To avoid unnecessary work 
and to prevent overcrowding of the laboratory force, it will be 
necessary to use care and judgment in the selection of samples for 
mechanical or chemical examination. 

At least one typical sample of soil and one of subsoil is to be sent 
to headquarters for every type recognized in the area except, pos- 
sibly, stony or gravelly types that have no agricultural value and 



1(S iNsriac'i'ioNs lo fjkld iwiriiKS. 

classilicalioiis. such ns meadow, wliich coTupriscs a (■()nsidera])le 
I'aiiuc in 1('x1iii'(' and color of material. 

The usual lai;-, l-'oi-m ^S. is lo Ise altaelied lo soil samj)les. This 
will uive a brief desci'i|)tion ol" Ihe soil, v.'iiich is needed to aid in 
idenlifyinu- ihe samj)le and to chock Ihe h-'ld mairs descri])tion of 
color. 'J'he area, collector, soil-type name, depth, and remarks, if 
necessai'y, ai'e lo he sho\\'n on ihiscard, and care is lo be used in 
tiix'inii', in dislance and direction from ihe nearesi lown or ])y land 
lines, Ihe exact local ion of Ihe s])o1 from which Ihe sample was 
obtained. .All wt'itiuLi' on Ihe 1a,u' ( lM)rm oS i should be in ink. 

This sam])le is lo re|)resen1 the average and usual condition of \ho 
type in l}i(> area and should l»e in accord with the lechnical descrip- 
lion liiven in ihe i-eport. The sample is to be used at head(piarters 
lo check the color, and, when necessary, the texture by mechanical 
analysis. A\'hen samples are sid>niil1e<l \ ai'yini;- to any extent from 
the typical conditions, the fact must be ])ron,uh1 out clearly. If the 
sample represents a ])hase rather than the 1y])ical development of a 
ty])(> the ])hase name .-^hoidd be uiven on the tau', as, for example, 
.Xorfolk sandy loam, deep phase, Cecil clay loam, eroded |)hase. 

Sami)les of soil submitted for special examination, such, for in- 
stance, as lime recpiirement determination, and s])ecimens of rock 
for identification, shoidd Innc the examinations desired carefully 
written in ink on the tai;-. It is \\('ll also to accom])any such samples 
with a letter statini': in detail what examinalions are desired and the 
reasons thei-efor. Careful descri])tion records should be kept by 
the field men of such sam])les in oi'der that lal)ora1ory i-esults can be 
properly lied to the saini)les examin(>d. 

The |)lan of numberinu ^^<'il samples sei'ially heretofore in us(^ 
has been done away \\ith and a new system inaugurated, under 
which the held man is to nundx-r the samples in the field and his 
nundx'i- is to be I'etained in the o(hc(% thus a\"oiding the confusion 
cause(l b>- ha\ ing the li<dd lunnber dii'ferent from the ollice num- 
ber. In the |)i-esent system each State has been gi\-en a nundjer 
consisting of two ligures; each area in Ihe Slate will be given anoth(>r 
nundxM- consisting of two figures, l-'or instance, Indiana lias been 
given the nund»er •':2S;" Marshall County, as the fourth area sur- 
veyed, is "01." All samples from tliat area should Ixnir the num- 
ber •'2SI)1," thus indicating the Slate an<l area, to which ar(> to be 



SOIL SAMPLES AND TYPE SPECIFICATIONS. 



19 



added the numbers of the individual soil samples (whether a top 
soil, subsoil, or any portion of the subsoil which may be separately 
collected), beginning with "01" and continuing consecutively. 
Thus, if a survey party in Marshall County had collected 35 sam- 
ples the last sample taken, whether of soil or subsoil, would be 
numbered ' ' 280435 . ' ' Every soil sample number will thus contain 
six or more figures. No periods or commas are to be shown in the 
number. A list of the several States and the number assigned to 
each are given in the following table. When parties are sent to 
new areas the State and area number will be given in the letter of 
assignment, to which individual sample numbers are to be afiixed. 
Each section of the soil collected should be given a different num- 
ber serially — the soil should be numbered as one sample, the sub- 
soil as another, and the deep subsoil, if a section of this is taken, as 
still another sample. 



of States and corresponding numbers to he used in numbering 




soil samples. 


10. Maine. 


35. North DaliOta. 


11. New Hampshire. 


36. South Dakota. 


12. Vermont. 


37. Nebraska. 


13. Massachusetts. 


38. Kansas. 


14. Rhode Island. 


39. Kentucky. 


15. Connecticut. 


- 40. Tennessee. 


16. New York. 


41. Alabama. 


17. New Jersey. 


42. Mississippi. 


18. Penns5^1vania. 


43. Louisiana. 


19. Delaware. 


44. Texas. 


20. Maryland. 


45. Oklahoma. 


21. Virginia. 


46. Arkansas. 


22. West Virginia. 


47. Montana. 


23. North Carolina. 


48. Wyoming. 


24. South Carolina. 


49. Colorado. 


25. Georgia. 


50. New Mexico. 


26. Florida. 


51. Arizona. 


27. Ohio. 


52. Utah. 


28. Indiana. 


53. Nevada. 


29. Illinois. 


54. Idaho. 


30. Michigan. 


.55. Washington. 


31. Wisconsin. 


56. Oregon. 


32. Minnesota. 


57. California. 


33. Iowa. 


58. Porto Rico. 


34. Missom-i. 





20 INSTRUCTIONS TO FIELD PARTIES. 

Soil specifications. — As soon as a field man lias established the 
existence of a tyi)e of soil in the area in snllicient area to map, 
whether an old and well-known ly])e or what is believed to be a 
new type, and after this is approved by tiie inspector, he is to 
write ont the specifications on one of the followinji^ forms and send 
it to the oflice for the information of the olllcial in charge of the soil 
snrvey and for the use of the correlation committee: 

Form No. GG. 

Spkcificatimxs of a Son, ok thi: l'^•:l)^!o^■T I'i.atfau Provinck. 

I-;.N('OlINTKREl> IN- TIIK Soil, SUKVKV OF (.\KF,A). 

(State). 

i •arcnl rork 

Color of soil 

Color of .siil)8oil 

'ro.vlnro of .soil 

'r(>x1 are of subsoil 

SInicluro of sul'soil 

Sulwt ratiun (if of mooifyini,' iinportaiicc) 

ll:ir<l])aii, if any 

I, oral modifiratioiis by wind and wafer (if of modifv-itiK importance) 

Drainajjo (if cxi-cssivo or tiericionf j 

■|\)pot;raphy 

Froross of formation: 

1 . Resiaual 

2. Colluvial 

F ield nan:o 

SaTnplp lun-ibers 

Remarks 

Patp Sit,'naturo 



i'orm Xo. G7. 

Si>i;ciFiCATiox.s OF A Sou, OF T!ii: KiVK!; Flood Flaixs FitovixcK. 

F^NCOUNTF.RKD I\ TIIF. Soil, SUHVF.Y OF ( ARF.A). 

(Statk). 

I'ari'iit pi'o\incc mali'riai: 

(«) Cllacial 

(b) Piedmont 



SOIL SAMPLES AND TYPE SPECIFICATIONS. 21 

Parent province material— Continued. 

(c) Appalachian 

(d) Limestone 

(e) Appalachian— Limestone 

(/) Glacial — Appalachian 

(g) Loessial 

(h) Coastal Plain 

(i) Coastal Plain— Piedmont— Appalachian 

(j) Residual Prairie 

Parent rock or soil material 

Drainage (well or poorly established) • ., 

First or second bottom 

Color of soU 

Color of subsoil 

Texture of soil 

Textm-e of subsoil 

Structure of subsoil 

Hardpan, if any 

Substratimi (if of modifying importance) 

Modification by salt water, if any 

Calcareous nature, if marked 

Field name 

Sample numbers , t-. 

Remarks 

Date Signature 



Form No. 68. 

Specifications of a Soil of the Limestone Valleys and Uplands Province. 

Encountered in the Soil Survey of (Area). 

(State). 

Color of soil... 

Color of subsoil 

Texture of soil 

Texture of subsoil 

Structure of subsoil 

Substratum (if of modifying importance) 

Parent rock 



22 i.xsriuKrnoNS lo field j'AirriEs. 



Hapilpan, if any 

Drainaijo (if excessive or defii-ieiiM 

'rop()irrai:)hy 

Process of formation: 

1. Kesidual 

•->. Coilnvial 

Field name 

Sample iMiml)ers 

Remarks 

Date Sii,niatiiri 



Form No. ii'.i. 

Sl'KClKU'VTION'S OF A Soil, OK TlIK (il-ACIAl, AND LoKSSIAI, ProVINXE. 

Encountered in the Son, Svhvev or (.\kka). 

(State). 

Soil derived from 

(a) Thick Ldacial till 

(b) Thick glacial till assorted or modified by jilacial waters and wind: 

1 . Morainic 

2. OiUwash pla.ins aiid fd led in vallevs 

(c) Thin Kdaeial till ! 

((f) Thiii srlacial till assorted or modified V)y rushin.t: .glacial waters and 

wind: 

1 . Morainic 

2. Outwash plains and filled in valleys 

{() I A)"ssial deposits ! 

Parent malcrial what principal rods 

( 'olor of soil 

Color of suhsDil 

Texture of soil 

'i'exture of s\ihsoil 

Structure of subsoil 

1 lardpan , if any 

Substratum (if of modifying importance) 

I )rainage 

Topotrrapb.y 

Field name 

Sample numln-rs 

Remarks 

Hate Signature 



SOIL SAMPLES AMD TYPE SPECIFICATIONS. 23 

Form No. 70. 

Spkcifications of a Soil of the Glacial Lake and River 'J'errace 
Province. 

Encountered in the Soil Survey of (Area). 

(State). 

Draina5;e (well or poorly established) 

Color of soil 

Color of subsoil 

Texture of soil 

Texture of subsoil 

Structure of subsoil 

Hardpan, if aiiy 

Parent material 

Substratum (if of modifying importance) 

Surface configuration (terrace, lake beds, hillocks, or ridges) 

Field name 

Sample numbers 

Remarks - 

I>ate Signature 



Form No. 71. 

Specifications of a Soil of the Appalachian Province. 

Encountered in the Soil Survey of (Area). 

, (State). 

Color of soU 

Color of subsoil 

Texture of soil 

Texture of subsoil 

Structure of subsoil 

Substratum (if of modifymg importance) 

Parent material 

Hardpan, if any 

Drainage 

Topography 

Process of formation: 

1. Residual 

2. CoUuvial 

42126—14 2 



24 INSTRUCTIONS TO FIELD PARTIES. 



Field name 

Sample number. 

Remarks 

Date 



Form No. 72. 

Specifications of a Soil of the Coastal Plain Peovince, 
Encountered in the Soil Survey of (Area) 

(State). 

Parent province material: 

(a) Glacial— Piedmont— Appalachian 

(6) Piedmont— Appalachian 

(c) Loessial 

(d) Calcareous 

(e) Residual Prairie 

(/) Coastal Plain— Reworked or Mixed • 

Color of soil 

Color of subsoil 

Texture of soil 

Texture of subsoil 

Structure of subsoil 

Substratiun (if of modifying importance) 

Calcareous nature, if marked 

Iron concretions, if any 

Hardpan, if any 

Drainage 

Hummocky surface, if any 

Prairie, if any 

Topography 

Field name 

Sample numbers 

Remarks 

Date Signatiu-e 



Form No. 78. 

Specifications of a soil of the— 

Northwest Intermountain Region. 

Great Basin Regio>'. 

Arid Southwest Region. 

Rocky Mountain Region. 

Great Plains Region. 

Encountered in the Soil Survey of the (Area). 

(State). 



SOIL SAMPLES AND TYPE SPECIFICATIONS. 25 

Soil type 

Province: 

Residual- 
Character of rock 

Glacial— 

1. Agencies— 

(a) Ice-laid 

< b ) Water-laid 

2. Parent material 

Lake-laid — 

Parent material 

Wind-laid— 

1. Loessial, recent 

2. Parent material 

Outwash Plain (includes coUuvial and alluvial footslope, alluvial fan and 

filled valley plains material) 

Coastal Plain- 
Parent material 

River Flood Plains- 
Parent material 

Note.— In indicating source of parent material state — 

1. Character of parent rock if known. If from sedimentary 

rocks, state vs^h ether cherty or chert-free limestone, sand- 
stone, shale, or alternating beds of above formations 

2. Age and name of geologic formation if determined 

3. Character of soil, or series name if derived from adjacent soil 

material 

Modified by: 

Erosion; aeolian, alluvial, coUuvial, or lacustrine agencies; weathering, 
drainage, leaching; accumulation of organic deposits, chemical pre- 
cipitates, etc. ; or by other agencies and conditions 

Regional topography: 

Mountain and hillslope or footslope, plateau or mesa surface, upland 
plain; morainic— groiuid moraine, lateral moraine, terminal moraine, 
etc.; kame, esker, outwash plain, glacial terrace, etc.; lake basin floor; 
beaches, deltas, spits, bars, embankments, cut and built terraces, etc., 
of lake basin and coastal plains; land slip terrace, fault terrace; debris 
aprons, slopes and floors of filled valleys, alluvial fans; alluvial valley 
slopes, flood plains and terraces; etc 

If terrace or mesa state approximate elevation above adjacent soil ma- 
terial 

Soil: 

Color 

Texture 

Depth 

Structure 

Organic-matter content 

Subsoil: 

Color 

Texture 

Depth 

Structure 

(If more than one subsoil or substratum occurs, describe each.) 

Other underlying material: 

1. Substratum— depth to, and character of material 

2. Hardpan— character, thickness, and position of material, if present. . 

Gravel and bowlders: 

1. Amount, size, and character 

2. Occurring in soil, subsoil, or both 



26 INSTRUCTIONS TO FIELD PARTIES. 



Rock outcrop: 

Character aud amount 



Occurrence of conspicuous concretions, volcanic dust, pumice or other frag- 
mental ejecta, iron crusts, nodules, calcareous material; mica, quartz, or 
feldspar particles or other recognized minerals, in soil and subsoil 

Surface configuration: 

1. Level, sloping, undulating, rolling, hilly, dissected, precipitous, 

smooth, irregular, hummocky, eroded, etc 

2. Relation to erosion, and adaptability to irrigation 

3. Drainage— relation to overflow, surface, and subdrainage 

Occurrence of alkali 

Native vegetation 

Present utilization 

Crop yields— heavy, light, or medium 

Special adaptation to crops 

Remarks: 



1. Note any essential or modifying features not already mentioned. 

2. Suggestions as regards correlation 



Laboratory sample Nos : 

Date Signature. 



Form No. 79. 

Specifications of a Soil of the Pacific Coast Region. 

Encountered in the Soil Survey of the (Area). 

(State). 

Soil type 

Province: 

Residual- 
Character of rock 

Glacial— 

1. Agencies— 

a. Ice-laid 

b. Water-laid 

2. Parent material 

Lake-laid— 

Parent material 

Wind-laid— 

Parent material 

Coastal Plain and older valley filling- 
Parent material 

Alluvial fan and recent valley filling. (Includes colluvial and alluvial 
footslope, alluvial fan, and filled valley plains material- 
Parent material 

River Flood Plains- 
Parent material 

Note. — In Indicating source of parent material, state: 

1. Character of parent rock, if known. If from sedimentary rocks 

state whether chcrty or chert-free limestone, sandstone, shale, 
or alternatmg beds of above formations 

2. Age and name of geologic formation if determined 

3. Character of soil, or series name if derived from adjacent soil 

material 



SOIL SAMPLES AND TYPE SPECIFICATIONS. 27 

Modified by: 

Erosion; seolian, alluvia], colluvial, or lacustrine agencies; weathering, 
drainage, leaching; accumulation of organic deposits, chemical pre- 
cipitates, etc.; or by other agencies and conditions 

Regional topography: 

Moimtain and hillslope or footslope, plateau or mesa surface, upland 
plain; morainic— ground moraine, lateral moraine, terminal moraine, 
etc.; kame, esker, outwash plain, glacial terrace, etc.: lake basin floor; 
beaches, deltas, spits, bars, embankments, cut and built terraces, etc., 
of lake basin and coastal plains; land slip terrace, fault terrace; debris 
aprons, slopes and floors of filled valleys, alluvial fans; alluvial valley 
slopes, flood plains, and terraces, etc 

If terrace or mesa state approximate elevation above adjacent soil ma- 
terial 

Soil: 

Color 

Texture 

Depth 

Structure 

Organic-matter content 

Subsoil: 

Color 

Texture 

Depth 

Structure 

(If more than one subsoil or substratum occurs, describe each.) 

Other underlying material: 

1 . Substratum , depth to, and character of material 

2. Hardpan; character, thickness, and position of material, if present. . . 

Gravel and bowlders: 

1 . Amount, size, and character 

2. Occurring in soil, subsoil, or both 

Rock outcrop: 

Character and amount ._. 

Occurrence of conspicuous concretions, volcanic dust, pumice or other frag- 

mental ejecta, iron crusts, nodules, calcareous materia], mica, quartz, or 

. feldspar particles or other recognized minerals, in soil and subsoil 

Surface configuration: 

1. Level, sloping, undulating, rolling, hilly, dissected, precipitous, 

smooth, irregular, hummocky, eroded, etc 

2. Relation to erosion and adaptability to irrigation 

3. Drainage— relation to overflow, surface, and subdrainage 

Occurrence of alkali 

Native vegetation 

Present utilization 

Crop yields— heavy, light, or medium 

Special adaptation to crops 



Remarks; 

1. Note any essential or modifying features not already mentioned. 

2. Suggestions as regards correlation 



Laboratory sample Nos 

Signature. 
Date 



28 INSTRlIC/nONS TO FIEFJ) TARTIES. 

Cakk of Instruments. 

Too inucli emphasis can not l)e laid u})()ii (lie importance of care 
ill liaudling and transporting instrnments. Every employee in- 
trnsted with instruments in the field will be expected to protect 
them from undue wear and to return them to the custodian in fit 
order for use . 

Accounts. 

Reimbursement accounts shoidd be sul)mitted ])romptly at the 
close of each month, and must ])e rendered in strict accordance 
with the ])rovisions of the J)ei)artnient. 1^'iscal IU\2:ulations. A 
copy of these reguhitions should be in the hands of every field 
employee, and may be obtaiiuMl throuuh the ollice of the chief 
clerk of the bureau. 

Leave of Ausexce. 

A copy of the regulations is furnished all emi)l(»yees, and a strict 
observanci^ of these regulaliotis is enjoined u])on every employee. 

1^'tELI) ( )UTFIT. 

The outfit for field work consists of the following for each member 
of the party: 

Soil auger, 40-inch. 

Geologist's hammer. 

Notebooks. 

Field diary. 

Set of colored pencils. 

Base map. 

Bottle of blue litmus paper. 

liottle of red litmus paper. 

Small bottle of hydrochloric acid. 

Sacks and tags (Form .'■)S) for collecting samples of soil. 

Soft pencils. 

Acquisition Form No. f50. 

Subvouchers for livery hire, meals, and lodging, Form 4 A. 

Kxpense accouTit sheets, Form No. 4. 

Mail forwarding cards, Form (-2. 

Form ().S, lor transferring proi)erty. 

ofllcial telegram blanks, l<\)rm E 1. 

Supply of stationery. 



FIELD OUTFIT. 29 

Copy Instructions to field men. 

Copy of Bulletin No. 96. 

Copy of Topographic instructions of the United States Geological Survey. 

Copy latest edition Fiscal regulations. 

Address cards, Form 50. 

When doing traverse work each member of party should have a 
complete planetable outfit, including: 
Planetable. 
Odometer. 

Alidade, with chain scale attachment. 
Alidade case. 
Paper of small needles. 
Supply of No. 4-H, 6-H, and 9-H pencils. 
Pencil erasers. 
Ink erasers. 

Leather case for holding planetable top and maps. 
Fine-textured sandpaper for sharpening hard pencils. 
Supply of cover paper for protecting field sheets. 
Supply of thumb tacks. 

The man in charge should have a supply of: 
Planetable paper. 
Tracing cloth. 
Triangles. 
Straight edge. 
Ruling pens. 
Crow-quill pens. 

Waterproof ink— red, blue, and black. 
"Weekly itinerary sheets. Form 140. 
Pliers. 

Speciacation sheets for provinces represented in the area, as follows: 
Form No. 66, Piedmont Plateau Province. 

67, River Flood Plains Province. 

68, Limestone Valleys and Uplands Province. 

69, Glacial and Loessial Province. 

70, Glacial Lake and River Terrace Province. 

71, Appalachian Mountains and Plateau Province. 

72, Coastal Plain Province. 
Northwestern Intermountain Region. 
Great Basin Region. 

78, Arid Southwest. 
Rocky Mountain Region. 
.Great Plains Region. 

79, Pacific Coast Region. 



30 INSTRUCTIONS TO FIELD PARTIES. 

Ill addition to the above, parties equipped for making alkali 
surveys should add the alkali outfit- 
Electrolytic bridge. 
Cell. 

Mixing cups. 
Spatula. 
Thermometers. 
Burettes. 

Measuring receptacles. 
Extension augers. 
Pipe wrenches. 
Filter pump. 
Screw driver. 
Metallic tape 50 feet long. 
Mailing cases. 
Water bottles. 

Additional supplies required for special purposes, such as sketch- 
iiig cases, tally registers, field glasses, and canteens, maybe obtained 
upon the regular requisition Form No. 60 as needed. In sparsely 
settled areas a complete camp equipment will be provided. 

The loss of or damage to any supplies should at once be reported 
to the office, with explanation of the cause of such loss or damage. 
(See Form No. 25 below.) 

United States Department of Agriculture, Bureau of Soils. 

Certificate of Property Lost or Beyond Repair. 

(P.O.) 

, 191 . 

I hereby certify that the following articles 

for which is accountable have been 

("Lost," "broken beyond repair," or "worn out," as the ca^, may 1 e.) 

in the following manner: •. 

(Signature) 

(Title) 

Approved: 



In Charge. 
is hereby responsibility for the 

of the above-enumerated Government property, the value of which is 

% , and the property clerk is authorized to drop said property from 

his returns. 



Chief Clerk of Bureau. 



INSTRUCTIONS TO FIELD PARTIES. 31 

Immediately upon learning of a new assignment the man to have 
charge should communicate with the office to ascertain what sup- 
plies will be needed in the new area, advising the office as to sup- 
plies on hand which may be used in the new area. Whenever 
possible arrangements should be made by correspondence with the 
office for shipment of the necessary supplies in time to reach the 
area so as to avoid delay in the field work. 

BASE MAPS. 

A detailed soil map is usually published on a scale of 1 inch to 
the mile; reconnoissance soil maps on a scale of 4 or 6 miles to the 
inch. The actual field mapping in a detailed area may be done 
on a scale of 1 inch to the mile or 2 inches to the mile according to 
the judgment of the field man, the scale of mapping depending on 
the complexity of the soils in the area. This is usually possible 
to determine in the preliminary examination in company with the 
inspector. 

The base maps furnished by the office consist, where available, of 
sheets of the topographic atlas of the United States published by 
the United States Geological Survey. When these are published 
on the scale of 6 2roo (about 1 inch to the mile) or on a larger scale, 
they can usually be used directly as the base map for the soil map- 
ping. When published on the^smaller scale they may be enlarged 
by photography for use as a base map for detailed soil mapping or 
they may be used merely as a guide in getting over the area accord- 
ing as the correctness and adequacy of details permit. 

The method of construction of topogi-aphic sheets, including the 
units, the projection, the methods of showing Land Office corners, 
boundary monuments, triangulation stations, etc., and the sym- 
bols used to express topographic and other physical features, 
including cultural features and hydrographic features are given in 
"Topographic Instructions of the United States Geological Survey," 
which should be consulted as a matter of information by all field 
men. 

When topographic sheets are not available. Land Office township 
plats of the area, if these can be obtained, will be furnished. These 
are on a scale of approximately 2 inches to the mile and may be 



32 INSTRUCTIONS TO FIELD PARTIES. 

used directly for the mapping of soils or as guides for the prepara- 
tion of the base map. 

Where county maps based upon Land Ofhce plats are furnished 
as a base, the size and shape of the sections should be most carefully 
checked with the odometer and planetable. In all cases, no official 
Government map or any county map published for commercial 
purposes which is more than a few years old should be used as a 
base map without careful scrutiny to discover possible errors. 

Making a Base Map. 

The making of a base map consists essentially of plotting on paper 
the distances and direction of physical features and the use of 
names and symbols in indicating the character of these different 
features in such a way as to convey an intelligent and correct 
impression of the character of the country. To measure distances, 
the Bureau of Soils generally uses the odometer for a so-called wheel 
traverse. Where the wheel traverse can not be made on account 
of the character of the country, a foot traverse or simple triangula- 
tion is resorted to. To determine directions, a simple form of 
planetable or sometimes a compass or an army sketching case is 
used. 

Measuring distances. — In the ordinary detailed surveys road 
distances are measured by the revolutions of a buggy wheel, the 
circumference of which has been carefully determined to the near- 
est tenth of a foot by a steel tape. The number of revolutions 
made by the wheel between two4|iven points is usually recorded on 
an odometer or revolution counter. Given the circumference of 
the wheel and the number of revolutions of the wheel between two 
given points, the distance in feet can easily be calculated. 
Obviously 100 revolutions of a wheel 9.2 feet in circumference 
differ materially from 100 revolutions of a wheel which is 11.2 
feet in circumference. For plotting measured distances upon a 
map, a boxwood rule called a chain scale is used with divisions 
equaling one-fiftieth of an inch, which on a scale of 1 mile to the 
inch would be equivalent to one-fiftieth of a mile. For conven- 
ience in plotting distances, the number of revolutions equaling one- 
fiftieth of a mile for wheels of different circumferences have been 



MAKING A BASE MAP. 



33 



computed and are given in a table, so that for awheel of a given size 
a certain number of revolutions are found to be equivalent to so 
many scale divisions and the distance is therefore plotted on the 
paper by use of the chain scale from the number of revolutions as 
fiftieths of a mile. 

The odometer.— The odometer (see fig. 2) in general use is the Bell 
revolution coun- 
ter. The red hand 
registers each rev- 
olution of the 
buggy wheel from 
to 100; the yel- 
low hand registers 
each 100 revolu- 
tions up to 4,000, 
and the blue hand 
registers each 
4,000 revolutions 
up to 40,000. With 
each revolution of 
the wheel, the red 
hand moves one 
space on the outer 
circle of the dial, 
completing the 
circuit in 100 rev- 
olution s of the 
wheel. When the 
red hand has gone 
around once and 
back to zero the yellow hand moves one space on the inner circle, 
and when the yellow hand has completed the circuit the blue hand 
moves one space forward on the inner circle. In reading the yel- 
low hand it is necessary to be very careful, since the yellow hand 
begins to move after the red hand passes 90 and may reach the next 
space division on the inner circle before the red hand reaches zero. 
Reading the yellow hand one space forward before the red hand 




-O.ioi'aeter. (Patented.) 



34 JNSTiaiCTlONS TO FIELD TARTIES. 

had reached zero would mean an error of 100 revolutions too great. 
Care must be taken, therefore, at this place in reading the revolu- 
tions of the red hand to see that the correct hundreds as indicated 
by the yellow hand is taken. 

The odometer should be clamped to the front axle close to the 
right wheel, face backward. It can be fastened on the axle with 
an iron clip or with a strong leather strap and a wooden wedge to 
tighten the strap. The spur wheel of the odometer should be 
placed within one-third to one-half inch of the hub and so arranged 
that it will revolve in essentially the same plane as the buggy wheel. 
The spur is turned through a part of a revolution with each revo- 
lution of the buggy wheel by means of a trip pin, consisting of a 
headless wire nail or round spike driven into the end of the hub, or 
better still, by a pin fastened in an iron band which fits around 
the hub and can be attached or taken off very easily. The trip 
pin should be bent to whatever angle is necessary to make it pass 
freely under the spur wheel of the odometer, striking the cogs about 
one-eighth inch from their ends. The buggy wheel should have a 
minimum of play on the axle, or else the trip pin may not operate 
the spur wheel properly. An odometer not in good working order 
should not be used. 

In case the traverse man has no odometer he can count the revolu- 
tions of the wheel as a temporary expedient. To do this he should 
tie some conspicuous object, such as a piece of white cloth or a 
small bush, to a spoke of the wheel. Coimting the revolutions holds 
the attention too close for the performance of the best work, espe- 
cially in the mapping of soils, and should not be substituted for the 
odometer except when absolutely necessary. 

The chain scale. — Having determined the number of revolutions 
of a wheel of known circumference between two points, it remains 
to plot this distance on the paper in the easiest way. This is done 
by the use of a chain scale, the construction of which is as follov/s: 

The chain scale used in the field work ( onsists of a small light 
boxwood ruler (see fig. 3) about 1\ inches long with beveled edges 
faced with celluloid, upon which a United States standard scale 
has been cut. Upon one side marked " 50 " the scale is in black and 
50 divisions represent 1 inch, or 1 mile if tlie scale of the map is 1 



JNIAKING A BASE MAP. 35 

mile to the iuch. Each division on tliis side of the scale represents 
one-fiftieth of an inch or one-fiftieth of a mile on an inch to the mile 
scale. 

The other side of the chain scale has the number 5,280 and the 
scale divisions are in red. On this scale there are 52.8 divisions to 
the inch, or 52.8 divisions will represent a mile on the scale of an inch 
to the mile. As there are 5,280 feet to the mile, one division on this 
scale will equal 100 feet on an inch to the mile scale. This side of 




Fig. 3.— Chain scale. 

the scale marked in red figures coming under the number 5,280 
must never be used in connection with the traverse unless the dis- 
tances are calculated in feet, but must always be used in the 
traverse where the distances are measured in feet. 

The following table is arranged for the ready conversion of num- 
ber of -revolutions of the different size buggy wheels directly to the 
chain scale divisions of fiftieths of an inch or fiftieths of a mile 
(1 inch=l mile scale), thus obviating the necessity of reducing the 
number or revolutions to the number of feet traversed: 



36 



INSTRUCTIONS TO FIELD PARTIES. 



Scale divi- 
sion. 



Circumference of wheel in feet. 



tV n^ile 



9.5 9.6 9.7 9.8 9.9 10 10.110.210.310.410.510.6 



10.710.8 



Number of revolutions of wheel. 



11 
22 
33 
44 
56 

67 
78 
89 
100 
111 

122 
133 
144 
155 
167 

178 
189 
200 
211 
222 

233 

244 
255 
266 

278 

289 
300 
311 
322 
333 

344 
355 
366 
378 
389 

400 
411 
422 
433 
444 

455 
466 

478 
489 
500 

511 
522 
533 
544 
555 



110 

121 
132 
143 
154 
165 

177 
188 
199 
209 
220 

231 
242 
253 
264 
275 

286 
297 
308 
319 
330 

341 
352 
363 
374 

385j 

396! 
407 
418! 
429! 
440 



11 
22 
32 
43 

54j 

65 

75; 

86! 
97! 
108 

119 
129 
140' 



152 151 
163 162 



392 388 



451 1 446[ 442 
462! 457 453 



473 468 
484' 479 
4951 490 



506| 500 496 
517 511 506 
528 522 517 
539| 533| 528 



10 
21 
31 
41 
52 

63 
73 
84 
94 
105 

115 

126 

136 

14 

157 

169 167 

180 178 

190 188 
201 

211 209 

222' 220 
232 231 
243 241 
253 252 
264! 262 

275 272 
285 282 
296' 293 
306 303 
317 314 

327 324 

338 334 

349 345 

359 355 

370 366 



412 408 
422 418 



437 433 

448 444 



104 103 

114 113: 

124 123l 

135[ 133' 

145 144 

155 154i 



429 
439 
450 
460 
471 

481 
492 
502 
513; 508 
5231 518 



164 
174' 

185' 
195: 
2041 

214 
224 
235 
245 
256 



163 161 
173! 171 
183 181 
193 191 
2031 201 

213! 211 
223! 221 
233 231 
244 241 
254! 251 



267 264, 262 
277! 274! 272 
287' 284; 282 
297 295 292 
308 305 302 



315' 312 
325 322 
335' 332 
345; 342 
3561 352 

366! 362 
3761 372 
386 382 
39(V 392 
406 402 



318 
328 
338 
349 
359 

369 
380; 
390! 
400, 

410 

42l! 4161 412 

431 426! 422 

441 437! 433 

451 447 443 

462 457j 453 

472! 467j 463 

4821 478 473 

492' 488l 483 

503 498 493 

513 508| 503 



10 10 

20 20 

30 29 

40 39 

49 49 

59 59 

69 68 

79 78 

89 88 

99 98 

109 108 
119 118 
128 127 
138 137 

148i 147 

158! 156 

168| 166 

178! 176 

1881 186 

1981 196 

207' 205 
217t 215 

227 1 225 
237 235 

247 244 

2571 254 
267| 264 
277 274 
287 283 
296 293 

306' 303 



316 
326 
336 
346 

356 
366 
375 
385 
395 

405 
415 
425 
435 
445 

454 
464 
474 
484 
494 



313 
323 
332 
341 

351 
361 
371 
381 
391 

401 
411 
421 
430 
440 

450 
460 
469 
479 
489 



MAKING A BASE MAP. 



37 



Scale divi- 
sion. 



1 
2 
3 

4 
5 

6 

7 
8 

10 

11 
12 
13 
14 
15 

16 
17 
18 
19 
20 

21 
22 
23 
24. 
25, 

26. 
27 
28 
29 
30 

31 
32 
33 
34 
35 

36 
37 
38. 
39. 
40 

41. 
42 
43 
44. 
45 

46 
47. 
48. 
49 
50 



Circumference of wheel in feet. 



10. 9' ll|ll.l'll.2|ll.3|ll.4|ll.5|ll.6|ll.7|ll.sjll.9l 12;12.l|l2.2 
Number of revol utions of wheel. 



10 


10 


10 


9 


9 


9 


9 


9 


9 


9 


9 


9 


9 


19 


19 


19 


19 


19 


18 


18 


18 


18 


18 


18 


18 


17 


29 


29 


29 


28 


28 


28 


28 


27 


27 


27 


27 


26 


26 


39 


38 


38 


38 


37 


37 


37 


36 


36 


36 


35 


35 


35 


48 


48 


48 


47 


47 


46 


46 


46 


45 


45 


44 


44 


44 


58 


57 


57 


57 


56 


56 


55 


55 


54 


53 


53 


53 


53 


68 


67 


66 


66 


65 


65 


63 


64 


63 


62 


62 


62 


61 


78 


76 


76 


76 


74 


74 


72 


73 


72 


72 


71 


70 


70 


87 


86 


85 


84 


83 


83 


82 


82 


81 


80 


80 


79 


79 


97 


96 


95 


94 


93 


93 


92 


91 


90 


89 


89 


88 


87 


107 


106 


104 


104 


103 


102 


101 


100 


99 


98 


98 


96 


96 


116 


115 


114 


113 


112 


111 


110 


109 


108 


107 


107 


104 


105 


126 


124 


124 


122 


122 


120 


119 


118 


117 


116 


115 


113 


113 


136 


134 


133 


132 


131 


129 


128 


127 


126 


125 


124 


122 


122 


145 


144 


143 


141 


140 


139 


138 


136 


135 


134 


133 


132 


131 


155 


154 


152 


151 


150 


148 


147 


146 


144 


143 


142 


141 


139 


165 


163 


161 


160 


159 


157 


156 


155 


153 


152 


151 


150 


148 


175 


173 


171 


169 


168 


167 


165 


164 


162 


161 


160 


158 


157 


184 


182 


180 


179 


178 


176 


174 


173 


171 


170 


169 


168 


165 


193 


192 


190 


188 


187 


185 


184 


182 


180 


179 


178 


176 


174 


202 


202 


200 


198 


196 


195 


193 


191 


189 


187 


187 


185 


183 


212 


211 


209 


207 


205 


204 


202 


200 


198 


197 


195 


194 


192 


222 


221 


219 


217 


215 


213 


211 


209 


207 


206 


204 


202 


201 


232 


230 


229 


226 


224 


222 


220 


218 


217 


215 


213 


211 


209 


242 


240 


238 


236 


234 


231 


229 


227 


225 


223 


222 


220 


218 


252 


250 


248 


245 


243 


241 


239 


237 


235 


232 


231 


229 


227 


?61 


259 

268 


257 
267 


255 
264 


'>5S 


9^(1 


248 
257 


246 
255 


244 
253 


241 
250 


240 

249 


238 
246 


235 
244 


271 


261 


259 


281 


278 


276 


274 


271 


269 


266 


264 


262 


259 


258 


255 


253 


290 


288 


286 


283 


280 


278 


275 


273 


271 


268 


266 


264 


262 


300 


298 


295 


292 


290 


287 


285 


282 


280 


277 


275 


273 


270 


310 


307 


305 


302 


299 


296 


294 


291 


289 


286 


284 


281 


279 


319 


317 


314 


312 


308 


306 


303 


300 


298 


295 


293 


290 


288 


329 


326 


324 


321 


318 


315 


312 


309 


307 


304 


302 


299 


296 


339 


336 


333 


330 


327 


324 


321 


318 


316 


313 


311 


308 


305 


349 


346 


343 


339 


336 


333 


331 


328 


325 


321 


320 


317 


314 


358 


355 


352 


348 


346 


343 


340 


337 


334 


330 


329 


326 


323 


368 


365 


362 


358 


355 


352 


349 


346 


343 


339 


338 


334 


331 


378 


374 


371 


367 


364 


361 


358 


355 


352 


348 


346 


343 


340 


387 


384 


381 


377 


374 


370 


367 


364 


361 


358 


355 


352 


349 


397 


394 


390 


386 


383 


380 


377 


373 


370 


367 


364 


361 


358 


407 


403 


400 


396 


392 


389 


386 


382 


379 


376 


373 


370 


366 


416 


413 


409 


405 


402 


398 


395 


391 


388 


3S5 


382 


378 


375 


426 


422 


419 


415 


411 


407 


404 


400 


397 


393 


391 


388 


384 


436 


432 


428 


424 


420 


417 


413 


410 


406 


402 


399 


396 


392 


445 


442 


438 


434 


430 


426 


422 


419 


415 


411 


409 


405 


401 


455 


451 


447 


443 


439 


435 


432 


428 


424 


420 


417 


414 


410 


465 


461 


457 


452 


448 


445 


441 


437 


433 


429 


426 


422 


419 


474 


470 


466 


461 


458 


454 


450 


446 


442 


438 


435 


431 


427 


484 


480 


476 


471 


467 


463 


459 


455 


451 


447 


444 


440 


436 



417 
425 
433 



38 INSTRUCTIONS TO FIELD PARTIES. 

Fool traverse.~l\\ wooded areas, cultivated fields, and generally 
along streams, in order to obtain distances between soil boundaries 
and physical features it is necessary to resort to foot traverse in 
which the distances are measured by the number of steps taken 
by a man or a horse. In estabhshing the relation between the 
steps taken and the distance covered it is necessary to measure 
with a steel tape or between land office stations or other known 
distances of a quarter or a half mile, the number of steps taken by 
the man or a horse at their ordinary gait. Having thus established 
the average length of a single pace, the number of paces between 
objects can readily be converted into feet and the distance so deter- 
mined between these objects plotted on the map, using the red 
figures on the chain scale and allowing 100 feet to each division of 
the scale. 

Triangulation. — The method of plotting distances which are in- 
accessible to a buggy and where the foot traverse can not readily 
be used, will be indicated under the description of the planetable 
and its use. 

Traverse notes. — In recording measurements of distance, whether 
determined with the odometer, in foot traverse, or by other means, 
tlie measurement figures of reading points — of set-up stations, turn- 
ing stations, soil boundaries, streams, branch roads, houses, etc. — 
should be carefully set down in the notebook by the man running 
the planetable. In recording measurements of the odometer tlie 
readings as indicated by the yellow hand and red hand should 
always be taken and set down, so that they can be referred to at 
any time and used as a check on the distances indicated on the 
map. A convenient method of recording such readings is to set 
them down along a line beginning at the bottom of the notebook 
page and proceeding upward as the work progresses. Figure 4 
illustrates the approved manner of recording traverse notes. The 
readings may be taken at a house, a turn in the road, a stream, or 
other prominent object, and the point roughly indicated on the 
perpendicular line by a short transverse line. The starting point 
should be thoroughly identified and in sketching line only sufficient 
deflection is shown at turns to indicate whether they are to the 
right or lef.t. A straight line may be used adding the letters "R" 



MAKING A P.ASE MAP. 



39 



yo/RK fR/V. 



790 
780 



Bf^owr/S ^ /=iD 



V 



Fig. 4.— Manner of recording traverse notes. 



51 
A I 




705 


-^16 


693 


3A 


659 


70 


635 


46 


612 


23 


589 


65 


567 


63 


544 


40 


504 


"eT 


490 


50 



2G_ 
79 



■^JKPT 



40 INSTRUCTIONS TO FIELD PARTIES. 



I 



or "L" to indicate deflection. The graphic method is, however, 
clearer and less troublesome. In the cut the sign X indicates set- 
up stations and the sign O the intermediate stations or turning 
points. The first column of figures represents odometer readings; 
the second column the revolutions between set-up or intermediate 
stations and other points, arrived at by taking the difference 
between a reading at a set-up or intermediate station and the 
reading of any other point in any given tangent. The measure- 
ment of wheel used in making traverse must be plainly indicated 
on the first page of the notes and thereafter at each change of 
vehicle. The direction of stream, soil boundaries, etc., can be 
conveniently indicated by the trend of these lines. 

When notes are kept in accordance with the method illustrated 
it will be possible subsequently to check the traverse work and in 
this way closure or other errors may frequently be corrected in the 
drafting room. Field notes so kept should be turned in with trav- 
erse sheets for use of adjuster. 

Determining direction. — HaAdng described the methods used in 
determining distances between two points, it remains to describe 
the methods used for determining the direction. Direction may 
be determined with the planetable, with a compass with sights, or 
with the army sketching case. The planetable traverse is based 
upon the principle that when the planetable is adjusted to a north 
and south position and lines are drawn thereon in accordance with 
sights taken through an alidade, these lines will take the proper 
direction without the necessity of reading angles. Where the com- 
pass is used as in heavily wooded areas or rough country, the angle 
has to be read off from the compass and then transferred to the 
paper by the use of a protractor. The army sketching case com- 
bines somewhat the features of the planetable, the alidade, and 
the compass. 

The planetable. —The planetable (see figs. 5 and 6) consists of a 
light wooden drawing board 15 inches square mounted on a tripod. 
Inserted in one edge of the board is a magnetic needle free to move 
through a space only of about one-half inch, protected on the top 
with glass, and having an adjustment on the outside which lifts 
the needle from its supporting pivot when not in use. At each of 



MAKING A BASE MAP, 



41 



the four corners of the board is a thumbscrew for holding the draw- 
ing paper rigidly against the upper surface of the table. The 
drawing paper in common use is a heavy paper mounted on cloth. 
The sheets are cut approximately the size of the planetable top 
with a rectangular piece cut out on the side where the compass is, 
so that the direction of the needle can be seen. The planetable 
board is attached to the tripod in such a way that it can be rotated 
rather easily and when set up for a sight it must also be so nearly 
level that the compass needle when thrown on to its pivot will move 
freely. 

The alidade. — Accompinying the planetable and as a necessary 
adjunct to it is an alid?de, which consists essentially of a brass or 
wooden ruler with 
at least one edge 
beveled for use as 
a straightedge in 
drawing straight 
lines on the paper. 
Attached to this 
ruler are two small 
sights approxi- 
mately 6 inches 
apart which can be 
folded down onto 
the ruler when not 

in use. The sight that is placed nearest to the eye in operating 
carries a narrow slit; the sight that is farthest from the eye in oper- 
ating has a wider slit in which a fine hair or silk thread is stretched 
in a vertical position. The alidade in common use in the bureau 
is made by attaching the two sights to a chain scale which has 
already been described and which carries on one side a scale of 
fiftieths of an inch, and on the other side a scale of 52.8 divisions 
to the inch. Figure 7 shows this alidade. 

In operating the planetable the first step after the table has been 
leveled is to swing the board until the needle of the compass is 
coincident with the north and south line in the compass box. 
This places and orients the paper in the line of the magnetic north. 




Fig. .5. — Planetable top. 



42 



INSTRUCTIONS TO FIELD PARTIES. 



A sharp-pointed No. 10 Cambric needle fitted with a convenient 
wooden cap (H' yealing-wax head is then stuck into the paper to 
represent the position which the planetable occupies witli respect 
to the location of the other points on the map of the area. The 
straightedge of the ahdade is then placed against the needle and a 
sight taken by rotating the alidade against the needle until the 
two sights of the alidade are directly in line with the distant object. 

Then, holding the ali- 
dade firmly down 
against the paper, a 
line is drawn from the 
needle point toward the 
object, the length of 
the line being eventu- 
ally determined by the 
measured distance. 

Care must be taken in 
all cases before taking 
the planetable off of its 
tripod support, and in 
all cases where the 
planetable is not actu- 
ally in use, to throw the 
needle off of its pivot to 
avoid injury to the steel 
pivot point. Under no 
circumstances should 
the compass in the 
planetable be carried 
from one station to an- 
other with the needle 
resting on the center 
pin. Party chiefs should lay special emphasis on this when in- 
structing field assistants. Leather cases are provided for the plane- 
table and these must invariably be used to protect the planetable 
when the board is not actually in use on the tripod stand. In 
shipping the planetable it must be carefully packed and protected 
and the tripods should have their heads protected by hay or excel- 




FiG. 6.— Planetable set up. 



MAKIIsG A BASE MAP. 



43 



sior covered with a piece of sacking or other substantial cloth. The 
needle box should be detached, carefully packed, and shipped 
separately. 

The accuracy of the orientation of the planetable is dependent 
upon the freedom from local attraction. For this reason it is neces- 
sary to avoid the use of the planetable near railroads, electric trans- 
mission lines, large bodies of steel or iron, and in certain regions of 
local magnetic variation. Furthermore, no plotted line should be 
greater than the length of the needle. It must be remembered that 
where the m a g - 
netic needle is 
used for determir- 
ing direction, and 
where this is free 
from local mag- 
netic influences 
and is free to move 
upon its pivot, 
the direction given 
is the magnetic 
north and south, 
which may differ 
materially from the 
true north and 
south to which the 
published map is 
to be oriented. 

The sketch map (fig. 1) showing the lines of equal magnetic decli- 
nations will be used as a guide in showing deviations of the com- 
pass direction from the true north and south, and the true north 
and south line, determined from this map or. from, other sources, 
such as the local surveyor, as well as the magnetic north and south 
line as determined by the compass, should be shown upon each 
planetable sheet as a guide to the adjuster in the proper orienta- 
tion and assembling of the sheets. This map shows the lines of 
equal magnetic declination in the United States as well as those of 
equal annual change, the former being shown by solid, the latter 
by dotted lines. The lines are moving westward, so that where the 




Fig. 



•Alidade. 



44 



INSTRUCTIONS TO FIELD PAKTIES. 



(lecli nation i^^ east il dcMTeases and where west it inereases annu- 
ally. Whenever it is net ])ossihh' to (h'l ermine the deelination 
from the maj) with a fair degree of accuracy the fiehl man should 
consuh- the county surveyor, who can usually furnisli this datura. 
When a laru;e area is beinu' surveyed it is esix'cially desirable to do 
this, as the declination may \ary considerably belween the eastern 
and western parts of the survey. 

Operation of the plaiictable. — In traxcrsing with tlie ])Ianetable 
it is usually essential to set up the instrument only at alternate sta- 
tions or points in the road. If the initial or starting point is at Sta- 
tion "A " (see lig. S) tlu^ planetal)!e is set np, Icxeled, and revolved 
until the com|)ass needle points north and south. The alidade is 
placed against tlie needle, which is inserted at the point "A'' and 




a sight is nuide on tlie point "b." A light pencil line is then 
drawn with a well-])ointed drawing i)encil along the edge of tlie 
alidade from "A" toward "b," extending beyond the estimated 
distance that "b" is from "A." The odometer is read, and the 
reading is recorded in the notebook. The team is t hen driven along 
the road to the first bend or point "b " and another odometer read- 
ing is taken to give the number of revolutions of the wheel between 
"A" and "b" and the reading recorded in the notebook. The 
team is then driven directly to the second bend in the road or Sta- 
tion "(\" where set-up is made. From the odometer reading re- 
corded in the note])Ook the distance from "A" to "b" is })lotted, 
and the needle is stuck at the point ''b." With this as a fulcrum 
the alidade is rotated until tlie points "b" and "C" are in line and 
a liuht ])encil line drawn, when from the nund)er of revolutions of 



maki:ng a base map. 45 

the wheel recorded between ''b" and *'C" the direction and dis- 
tance that "C " is from ''b " can be plotted. When the point '^C " 
has thus been placed upon the paper with respect to "b," the 
needle is transferred from the point "b" to "C," and the direction 
of "d" is determined, the distance or length of the line to be plotted 
when a set-up is made at " E . " And so the traverse goes on by set- 
ting up at alternate turning points and making forward and back 
sights. 

In traversing a road, houses or other points standing immediately 
adjacent to the road may be placed upon the map from the odom- 
eter readings, estimating the distance of the object from the road, 
when the distance is small . When the house or other point which 
it is desired to show is some distance from the road, a distance rep- 



I 

Fig. 9. — Diagram illustrating location of points by intersection during progress of 
road traverse. 

resented by at least a number of divisions of the chain scale, it can 
frequently be located with sufficient accuracy by intersection or 
triangulation as follows: When at "b " a house "H " is seen, a sight 
may be taken and a line ' ' bH " may be drawn giving the direction 
of "H" from "b." Similarly, from Station "C" another sight on 
"H" may be taken and a line drawn giving the line of direction 
"CH." This line will intersect the line "bH, " and the point of 
intersection will give with sufficient accuracy the position of the 
house at "H." (Fig. 9.) It is obvious that the nearer a right 
angle the angle "bHC " is, the more accurate the location will be, 
as a very acute angle — such, for example, as the angle "bHBa"— 
may not indicate distance from "b" to "H" so accurately as the 
observation from "C," which cuts the line "bH" nearly at a right 
angle and which, therefore, locates the object "H " from the station 



46 



I Nsiia (rrioNS lo i-ikld parties. 



''!)" iiuich more :icciii'al<'l\- than would an ohsorvatioii I'roin 
'•Ba." 

Ill liax'crsiiiti; roads all si ream crossiut^s, cross roads, side roads, 
])roiniiKMit trails, boundary lines. Land OfKce corners, railroads, 
lroll(\v lines, and other cultural and ])rorninent to])(),t>:ra])liic features 
niiist he accurately indicated hy the odometer readin^u' or hy foot 
traverse, as the case may be. 

In traversino; railroads the line of (lirection may l)e extended by 
means of for(^ and back sights. If in exceptional cases it becomes 
necessary to rely on the needle, it is important to set up the plane- 
table a sullicient distance from the rails to prevent their influence 
on the needle. In traversing a railroad distances can be obtained 
by measuring a rail and counting the numl)er of rails between 




Vui. lO.-illiKlrali 



set-U]) stations. Tlie h'uglh of the rails nuisl be checked l)efore 
starting. 

The usual nu'tiiod of ])ro(('dure without us(^ of com])ass is as 
follows, taking ligure 10 as an ilhislratioii: 

("lose down com])ass needle and orient on highway or other 
])reviously i)lotted line at "A."" placing ])lanetable over rail, sight 
to end of straight section of road at II. count the rails (on same side 
of track throughout tiie traverse), set u]) at " H "' and i)rick off dis- 
tances from "A " to "!>." Orient at "l>" by swinging planetable 
until the .sight through the alidade placed along ])lotted line " Ali '' 
corres])on(ls with the line of sight, from "!>"' to '"A." then reverse 
alidade sight on break ' in rails at "('." Work to "(','' ])lot dis- 
tance, and orient as before by sighting on l)reak in rail at '*B." 
Xow si^ht ahead to next set-iu) station at "D."" and continue in 



1 A custoinary iin'lliod of idtMitifj^iTi;; break in rails iis('(l as txicksight Ls to choose 
a break near or opposite a telegraph pole or to slip a small pieee of paper in the 
break. 



MAKING A BASE MAP. 



47 



this manner with the traverse, drawing lines between stations and 
plotting just as in highway traversing, and drawing in the curves 
as the work progresses. On sharp curves shorter sights should be 
taken. 

Road lines, houses, and other lines to remain permanently on 
the map should be made with hard pencil, either 9 H or G H, and of 
sufficient size to be at all times legible. When the map is soft on 
account of damp- 
ness of the atmos- 
phere it may be 
better to use a 6 H 
or even a 4 H pen- 
cil than the sharp- 
pointed, cutting 
edge of a 9 H. 

The compass. — '- 
When the plane- 
table can not con- 
veniently be used, 
as in densely 
wooded areas or 
r u g h mountain 
areas, and often 
in traversing 
streams, the com- 
pass with sight at- 
tachments, shown 
in figure 11, may 
be used. The com- 
pass used by the 
bureau has a 
double scale attachment, so that the inner scale may be revolved 
by use of a vernier to adjust for magnetic declination, so that the 
sighting can be given either on the basis of the magnetic north or 
the true north. The base of the compass is beveled and is gradu- 
ated on two sides in inches and on the opposite side in degrees 
from to 90 for use as a protractor. In sighting for direction with 
the use of one of these compasses, the angle obtained from the 

42126—14 3 




Fig. 11.- 



ompass. 



48 INSTRUCTIONS TO FIELD PARTIES. 

reading of the magnetic needle on the scale is transferred to the 
map by the use of the protractor (fig. 12) on the base of the com- 
pass or by the use of a celluloid protractor furnished by the bureau 
for this purpose. 

The army sketching case} — The army sketching case (fig. 13) 
consists of a planetable board, 6 by 12 inches, to the lower right- 
hand side of which is attached a compass box with floating dial, 




Fig. 12.— Protractor. 

3 inches in diameter, beveled on the edge and graduated to 360 
degrees. 

A protected opening in the compass box permits the graduated 
dial to be read either from above or when the board is held level 
with the eye of the observer. 

In line with the center of the compass and parallel with the edge 
of the board are placed rifle sights, which are used as an alidade 
in taking bearings. 

On the upper side of the board is mounted a circular plate, 6 
inches in diameter, and pivoted at the center. This plate is 
attached to an L-shaped base, at the upper end of which is a cyl- 
inder, through which passes a rod parallel with and secured to the 
top of the board. 

1 Wilson's Topographic, Trigonometric, and Geodetic Surveying, p. 166 b. 



MAKING A BASE MAP. 49 

To this plate may be attached aluminum protractor cards bearing 
concentric scale graduations; a different card being used for each 
scale used in mapping. The plate and card can be slid on guides 
from side to side of the board and clamped at any desired position. 
Over this protractor travels a sheet of vellum tracing paper which 
is wound on friction rolls. 

To sketch a traversed route or make a topographic map with this 
instrument, hold it level in one hand and read the compass bearing 
by the gun sights on some point in the route of travel. 

Loosen the clamp of the circular plate carrying the protractor 
and revolve the plate until the degree mark corresponding with 




Fig. 13.— Army sketching case. (Patented.) 

the bearing aheady determined coincides with the index line of 
I the clamp and then clamp the plate. 

The above operation insures plotting the map lengthwise of the 
paper. 
! Draw a line through the zero and 180° mark of the protractor to 
j form the magnetic index line. 

Being now prepared to proceed with the survey, sight to the 
point to be occupied as the next station, release the needle, and 
read the bearing of the dial. 



)ll 



\ ^ I i;m I k I \ > i( » I 1 1 I I) I- \i; i 1 1^. 



.-Ill- :i [Hiiiii Mil I Ik' \>:\ ]<'■]■ ir^Mi w liidi i In- 



I... 



t I 111' pldl |-;m1(,| I'X.hi l\ ilii.li'i II ;ili(| i|l;i\\ ;i III 



..\.T iIh' I.mIijI 111- llli'' "II ill'' 1i|m||:ii |M|- w 1 1 1 . ', i ., ,>t. ■-],,, n 1 1 - wilii 
i1m- in, 111, rj iv;nl I.;. lIl,' r, ,,| l | i;l -- . 

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IM ll,,. -,;ilr .Ml |,|m\,.,|. 

HnM iIm' |i:i|H-|- on 111,. I„,iln;,, r ,|1,t iiumI i1m' -.•<•.,;,,! -I;,ll ,|1 i- 

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II- ,','llh'r I- lllnlrr ill,' [H.liil ,M',lll.l.',i. ;in,| |,M.> .'-.I ;i- ;il llic lir-l 

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>t';i,| ill,' !,,';iri!,'j 1 1, II , ;llii| 'jl-iiw ;i -IkTI ll lie oil ! !ic | ,;l ] )( 'f ( , \ , 'f 1 li,' 



liiM' 111 ilic |,i'(,i r;M'l<,r li;i\iii'j- ill.' -am.' iiiiinl),'i-i wj. < in n'a.liiiiL; 
ill.' !i.'\i -i;iii,.ii. a-aiii -i"lil ill.' ..i.j.'.-i ami ■ I I'a w a Inu' a- l/cior.'. 

Til.' I Ml.'!-.'. I 1 l' ill.-,' l\\,l lin.'- 1- ill,' |,m;iII,.|1 ,l,-ii-,',|. 

Til.' illii-ifaii .11. li.jMr.' I 1. L:i\< - an i.lra -I iln' iPiniln'i- ..| -1m|,- 
.iihl -,'i i|)- I n;ii ii i- n,'.-..--a!-\ i . inak.' in in, ir-.' ..l' . : .n-: I'm Miil; 

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1^1,1 -'.-i.'n, i'.iiiT-. w.'ll alili'.iiL'ii n ' liii,'- "i ,■ 'iiin-.-ii .n ;ir,' -n,.uii 



Til.' .111 I- i:,k. 

ll(. !•■ ill.' Il_'lil 



pn ..1 a I 



ilan.'i;,!.!.' -ii.'.'i un.'i. 'n.'M 



MAKING A BASE MAP. 51 

Primary control. — An important feature of a geographical map 
of any kind is that there shall be certain traverse lines, objects, or 
points, whose actual position with respect to direction and distances 
from each other or with respect to other objects outside of the area 
shall be clearly known, in order that the position and shape of the 
area on the earth 's surface may be definitely fixed and that the 
direction and distances of all other points in the area may be 
relatively established. 

The Bureau of Soils does not attempt to make this primary con- 
trol as there are few areas in the United States which can not be 
tied up by distances and direction with points already established 
and obtainable from the records of the Coast and Geodetic Survey, 
the Geological Survey, the Lake Survey, and the surveys of the 
Army engineers. These records are utilized to the fullest extent 
and information drawn from them is furnished for use of the field 
men. 

The base-map making by the Soil Survey field man is solely for 
the purpose of soil mapping. In the construction of an entirely 
new base map, primarily no attempt is made to construct a map 
strictly accurate according to the requirements of geodosy. 

Maps of the General Land Office, the Coast and GoedeticSurvey, 
the Hydrographic Office of the Navy, the Corps of Engineers of 
the Army, the Mississippi River Commission, the survey of the 
Great Lakes, the national boundary surveys. State boundary sur- 
^veys, boundaries of national parks, forests, monuments, game and 
bird preserves, Indian and military reservations, land grants, 
surveys made by the Reclamation Service, Forest Service, and 
Bureau of Soils, will be furnished field men when available. 

The field man should not fail under any circumstances to tie his 
traverse to a number of such points as have been accurately located 
by other agencies, and the greater the number tied to the better 
will be the result of final adjustment of his work. 

Secondary and minor control. — While the bureau does not attempt 
to establish primary control lines or points, but furnishes such data 
as are available from other recognized authorities, it is essential 
that the field men of the bureau tie up their traverse work with all 
such control points or lines as can be furnished, and with estab- 



52 INSTRUCTIONS TO FIELD PARTIES. 



raS 



lished range, township, and section lines, railway stations, mile 
posts, bridges, stream crossings, and other natural or culturi 
features. It is also necessary to control or check up the trave 
in a number of ways. 

If a traverse of a continuous road across the county is made as a 
base line, theoretically the road should be traversed in the opposite 
direction throughout its whole extent to see if the directions and dis- 
tances first made are confirmed. In practice this control is obtained 
with less expenditure of time by running small circuits. This 
is done by starting from some point on the main road, preferably 
from a primary control station or from a section corner or cross- 
roads, and running with the main road for a distance of, say, 5 miles, 
plotting in all railroad, stream, and other crossings, then taking a 
side road and traversing back to the point of departure. It is sel- 
dom that a circuit of this kind extending over 10 or 15 miles will 
come out exact. There is nearly always a closure error. This 
closure error must never be adjusted by the field man but must be 
shown as a closure error as indicated upon the accompanying dia- 
gram (fig. 15), and the adjustment left to the office. If this closure 
error amounts to more than five or six scale divisions there is 
something radically wrong in the traverse, and the traverse in this 
case should be run over or the error detected in the field and indi- 
cated on the map. These closure errors must never be shown in a 
town or village. The errors usually occur in reading the odometer 
or in plotting the odometer readings on the map, and these can ol'ten 
be detected by comparing the odometer readings in the notebook 
with the plotted distances on the map and the point of error thus 
quickly determined, or the errors may occur from the orientation 
of the planetable, due either to failure to level the board so that 
the needle will swing free or in subjecting the magnetic needle 
to the influence of steel rails, buggy tires, or other magnetic in- 
fluences. The utmost care must be taken in traverse work to avoid 
large closure errors. The two diagrams shown in figure 15 represent 
the traverse of a circuit of 10 or 15 miles. One of them (1) shows 
a closure error of less than three scale divisions, which would be 
considered a good traverse; the other (2) shows a closure error of 
considerably more than three scale divisions, which indicates a 



MAKING A BASE MAP. 



53 



poor traverse due to mistakes in reading or in plotting the odometer 
readings or to errors in taking directions; in other words, showing 
errors in direction or distance, or both. An expert traverse man 
can tell pretty closely from an examination of the work and the way 
the lines approach each other at the starting and ending points 
whether to seek for the error in the odometer readings or in the com- 
pass readings. It is helpful in the adjustment of traverse errors 
in the office if the direction of main traverse is shown by small 




veasE POINTS 



Fig. 15. — Diagrams shoMng good and poor traverse. 



arrow points along the road in the direction traverse has proceeded. 
The curved arrow which is used to call attention to the closure 
error should always be drawn from, the ending point toward the 
tying point and in the same direction as the arrows placed along 
the road. These curved arrows showing the point of closure 
errors should always be drawn with red ink, so as to make them 
distinct and to distinguish them from all pencil and black ink 
lines on the map. Care must be taken in working near the edges 



r,4 



INSriU (TIOXS lO inVAA) I'AiniKS. 



of a pl:iii('lal)l(^ sIkmM Io sto]) Iho Iravcrso at somo easily identifipd 
point . as a ci'ossroad, a railroad crossinu', stnMin crossing', orprominent 
l)('iid in ihc road, wliich sliould 1)0 lied to wIumi workinij: adjoiiiinii; 
sheds ill oi-der llial the adjustment of tlie work on the different 
sheets may pro])erly be made. Only one point should be trans- 
ferred to an adjoining sheet, and all work on the second sheet must 
be started and controlled from this initial ])oin1. 

When the land is sectionized no traverse line or road should be 
run more than •") mile-; without bein^- tied to some section or other 
recoonized land line or corner. While it is not always ])Ossible to 
determine t'ac description of any land line or corner located or 
pointed out. ii can usually be done as a last resort by means of 
deeds or tax recei))ts. l^'or example, where 
the traverseman has pr()<>ressed as much as 
4 miles from the last |)oint where he tied to 
a land line or corn(^r, he should be^jin to 
cast about for a tie i)oint. On comin<? to a 
farmhouse he should exj)lain wdiat he is 
doing and ask the ])rivile,ue of seeino; a deed 
or tax recei|)l of the land on which the farm 
is located. Suj)i)ose the recei))t described 
the tract as follows: E. h XE. i: SW. } Xlv 
}; XE. 1 SE. ], all in sec. 35. T. IM X., R. 
22 W. lie should plat the tract de.-^cribed. 
Eignre !(> is a ])lot of such a tract. The field man should then 
a-^k the farmer for the location of the east boundary line of his land 
an<l for the northeast corner or some other boundary line or corner. 
The traverse work should be tied to any corn(M- thus located. This 
is an extremely important mailer. The soil l)oundari(>s in such 
an area will be located by tlu^ user of a soil map largely by i-efer- 
ence to section or other land lines; therefor(\ the more often the 
traverse is lied to land lines and corners the more mnirly will the 
result (b'sired be accomplished. 

In a comparatively open (agricultural) country it is usually 
possible to get fretpient sights on some i)rominent object for 
instance, a church spire or ])eculiarly-shaped tree on a major 
elevation. Say the Iraverseman has set U]) or made a station at a 



1 n 




V 




V 


1 ^ 


^ 


^ 









V\(\. ir..— r.and liiifN plot 
led from <io^^■rii)ti()Tl ii 
lax re;ei!)l. 



MAKING A BASE MAP. 



55 



crossroad and located thereat a church; continuing the traverse, 
he would at intervals selected to give the largest angle approaching 
a right angle, sight back on the church spire, indicating by a short 
pencil line, lightly drawn, the result of each sight. For distances 
of one-half mile or over it is realized that the sight will be approxi- 
mate only, but at the same time if care has been taken in traversing 
and in setting up the planetable for these reference sights, they 
should prove of value to the adjuster, when used in connection 
with the field notes giving distances, etc., stations from which 




DOTTED LINE /NDICATBS /NCORRECT TfiA\^ERS£ 

Fig. 17. — Illustrating detection of error in locating point by intersection, as a 
result of an incorrect odometer reading. 

sights were taken on the church spire being noted in the field 
book. Two or three sights on a short circuit are sufficient. 

In the illustration (fig. 17) the sight from station No. 3 intersects 
the church spire and shows the position of station No. 3 to be 
correct, but suppose an error has been made in plotting the line 
between stations, 3 and 4, then upon producing the line obtained 
by sighting from station No. 4, the pencil line misses the spire 
by three scale divisions. The line of sight actually intersects the 
church spire, but by reason of the fact that station 4 is erroneously 
plotted on the traverse sheet, producing the line in pencil throws 
it three scale divisions south of the church for the reason that 
station No. 4 on the traverse is plotted short of the actual distance 
from station No. 3; i. e., the traverseman actually occupies on the 
ground the correct position, and in sighting carries a certain direc- 



-")(') 



!\si'i;rcTrf)X.s to fiki-d rAirriEs. 



tion from the church, but since on the traverse he occupies an 
erroneous position soulli of actual station and carries the same 
(liriMtiou from tlie church, the line obviously can not intersect 
ilic church spire on the traverse. By this means theerroris promptly 
located, and while it might not be necessary to rerun or correct it, 
tlu; traverseman would refrain from running any traverse line away 
from this portion of the circuit (from station No. 4 and beyond), 
l)ut always work hack to it, thus confining his error to the one 
circuit. This may be carried farther by th(^ traverseman and he 
iiuvy cut in by iulcrsection any other near-by ])rominent features 
ilial he is reasonably certain to see from future stations. 

If a uiain road ha-^ originally been carefully traversed, say across 
the tni verse sheet, to b ■ used as a bas<' line, then on starting the 




Fig. is.— Showing iiuMluxi of iiru'cJuro hi luniuiiu; circuils wliere a base line lias 
alroadv hctMi Iraverscij. 



general traverse each diverging road should betaken U]) successively 
as reached and the circuit closed as promptly as ])ossibIe. Figure 
18 illustrates this procedure. 

This short-circuit method would be especially useful in sections 
where the (Jeological Survey or other control is not obtainable. 
At the same time it should not l)e considered as anything more 
than a plan lo minimize errors of secondary traverse. 

The following illustration (figs. 19 and 20) shows a portion of 
four traverse sheet>; illustrating the incorrect and correct method of 
carrying over traverse work from one sheet to another. The ex- 
tensions beyond the boundary of the map used to tie on to the 
adjoining .sheets are indicated. These illustrations also illustrate 
th(! proper method of indicating closure errors. 

As the comi)leted map of an area must bedrawn often from lOor 15 
])lan(!table sheets and often small parts of sheets, it is very essential 



FEATURES TO BE STKnVN ON IVF \r. 57 

that each sheet be numbered and the place occupied by each sheet 
shown on a diagram representing the county or area as a whole to 
assist in the proper assembling of the work in the office. 

Features to be Shown on Map. 

The features that must be shown on all of the maps are of three 
general classes: First, culture or the works of man such as roads, 
railroads, houses, towns, cities, etc. ; second, water, including lakes, 
seas, ponds, canals, swamps, springs, etc.; third, soils. It is also 
sometimes advisable to show some of the more pronounced topo- 
graphic features, as mountains, cliffs, escarpments and high terrace 
lines. All such features should be shown by conventional symbols 
and lettering. 

All the work on the traverse sheets must be distinct, the lettering 
legible, and necessary corrections plainly indicated, so that when 
the work is turned over to the draftsmen it can be clearly under- 
stood by them. Strict attention to details will often save the delay 
of referring questions to the field men, as well as greatly facilitate 
the work of the office. 

Cultural features. — The following cultural features are to be shown 
on all soil maps by the conventional signs, adopted by the United 
States Geographic Board for use by all mapping departments of the 
Government and published in Topographic Instructions of the 
United States Geological Survey, pages 205 to 228; bench marks, 
boundary lines (civil), boundary monuments, bridges, buildings, 
canals and ditches, cemeteries, dams, ferries, fords, land corners, 
land grants, land survey lines, levees, life-saving stations, light- 
houses, mines and quarries, power lines, primary traverse stations, 
railroads, reservoirs, roads, trails, traimways, triangulation stations, 
tunnels. United States location monuments. United States mineral 
monuments, wharves, docks, jetties, etc. 

Roads. — Under roads are included all streets and roads, public 
and private.. Distinction is to be made between first-class and 
second-class roads, the former being shown by solid lines, the latter 
by broken lines. A simple method of marking consists of placing 
a figure or letter on each stretch of road, thus — 1, standing for first 



58 



iNSTiacrnoNS to fikm) rAirriES. 



SHEET A 



SHEET 3 




SHEET 2 




Fig. 19.— Incorrect method of carrying iruver.se from one slieet to another. 

All points A-l)-c-(l along margin of Sheet No. I transferred to Sheet No. 2. Trav- 
erse developed on Sheet No. 2 from several of these points. Result: Errors 
of Sheet No. 1 are distributed over everj- portion of Sheet No. 2, causing endless 
confusion. The dotted lines indicate traverse developed from point ''A '' alone 
{correct method); the full lines show development from various points "b-c-d" 
{incorrect method). By the second method, all errors are necessarily transferred 
to the various other sheets of tlie traverse (see slieet No. .'?), still further adding to 
the confusion.] 



FEATURES TO BE SHOWN ON MAP. 



59 



SHEET A 



4 



SHEET 3 



SHEET 1 


r^ 




-^-^ 


^ 


^ 


% 




v\ 


/ 






J v 


^ 




^ 


^-~~ 


\ 


I, 









SHEET 2 




Fig. 20,— Correct method of carrying traverse from one slieet to another. 

[One point only (A) transferred from Sheet No. 1 to Sheet No. 2. Traverse devel- 
oped on Sheet No. 2 from this point (A) only. Traverse lines approaching margin 
of sheets are "stopped" at definite points, i. e., stream crossings, or intersection 
of roads nearest marginal guide line (on either side of same). Note: Sheet No. 
1 shows poor, and Sheet No. 2 good traverse work.] 



GO INSTRUCTIONS TO FIELD PARTIES. 

class; 2, for second class. This should be done as the road traverses 
are run. 

The classification of roads is governed by the following criteria: 

First-class roads include all State, county, or other public roads 
in such condition as to be available for travel; all main or through 
roads in sparsely settled mountain or desert regions, regardless of 
condition; all city streets and park and cemetery drives. 

Second-class roads include all public roads which through disuse 
or neglect have become impassable or can not be traveled without 
risk (through roads in sparsely settled regions excepted in accord- 
ance with the foregoing paragraph); all neighborhood roads in 
rural districts (except those of sufficient importance to be regarded 
as through roads) ; all private roads, lanes, and stub roads to farms 
and country houses. 

In areas where public highways generally follow the section lines 
of the land survey the classification of roads is to be made with 
reference to ownership and permanency of location, rather than 
condition or amount of travel. Roads which are considered per- 
manently located include those along section lines and those which 
leave the section lines for short distances to avoid natural obstacles. 
Roads thus permanently located, when following a section line for 
one-fourth mile or more, are to be classed as first-class roads. Diag- 
onal roads not following section lines here and there are to be classed 
as private, unless they constitute the main through routes of travel. 

Lumber or wood roads generally are to be omitted, but any prin- 
cipal through lumber roads which may be properly considered 
permanent cultural features are to be shown by the second-class 
symbol. First-class roads should be drawn in by solid black lines, 
second-class roads by dotted black lines. In order that the pricked 
points may not be obscured it is suggested that the roads be inked 
up to the needle points, but not through them. 

Buildings. — The map must show all buildings of a permanent 
character, such as dwellings, public buildings, shops, factories, and 
other industrial establishments, by proper symbols; it should be 
reliable not only as regards their location, but also as regards their 
orientation — that is, the way each building is set with respect to 
the points of the compass. 



FEATURES TO BE SHOWN ON MAP. 61 

Uninhabitable dwellings, whether farmhouses or miner's or 
lumberman's cabins, are to be shown only when they constitute 
important landmarks in regions of sparse culture. 

Houses should not be shown conventionally contiguous to the 
roads, unless the actual distance that separates them from the edge 
of the right of way can not be plotted on the scale of publication. 

Detached houses in residence portions of cities, suburbs, and 
villages are to be shown separate wherever possible. When the 
scale does not permit individual houses to be shown, indicate the 
group by a solid block. 

Churches and schoolhouses . — Churches and schoolhouses are to be 
indicated by a cross; such cross should be attached to the house 
symbol, so as to point at right angles to the roadway and not neces- 
sarily to the north. When situated in the country local name 
should be given. 

Railroads. — Under railroads should be included all steam and 
electric railroads. All of these should be shown by the regular 
railroad symbol. Double tracks, railroad yards, spur tracks, and 
switches should be shown so far as the scale will permit. Separate 
railroad lines in juxtaposition should be differentiated by placing 
the crossties as shown on the symbol chart. Railroads within a 
roadway should be shown by fine cross lines not extending beyond 
the road lines. 

A railroad-station should be represented conventionally by a large 
or elongated house symbol placed across the tracks. 

Bridges. — All bridges of any consequence should be shown and 
the names of those across large streams should be given. Bridge 
symbols should be shown for all road bridges across double-line 
streams; all road bridges across single-line streams in sparsely 
settled regions or wherever the existence of the bridge is vital to 
the use of the road; all road bridges over canals not crossable other- 
wise; all important viaducts over railroads, railroad yards, roads, 
or streams. Ordinary bridges and trestles on railroads are to be 
omitted. The bridge symbol should also be omitted wherever in 
centers of dense culture its presence would tend to impair the 
legibility of the map; also on reconnoissance maps, except where 
it indicates important structures over streams otherwise difficult 
to cross. 



62 IXSTIiUCTIONS TO FIELD PARTIES. 

Fenies. — Ferries are to be shown by symbol wherever the 
stream is wide enough to permit; otherwise the ferry is to be indi- 
cated by the word. Names of ferries must be put on the map. 

Fords. — The symbol for fords is similar to that for second-class 
roads. The names of important fords should be put on the map. 

Trails. — In mapping trails the soil man should consider their 
relative importance as a means of communication. Thus, in 
mountain and desert regions, especially in the far West, where 
travel is largely by trail, he should take pains to map ev^y trail in 
use, giving its name, if known; in the more densely populated 
districts, where railroads and wagon roads are plentiful, he should 
show only such trails as lead up mountains or through unimproved 
areas not readily accessible otherwise. A mere "way through" 
not regularly traveled does not constitute a trail. 

Canals and ditches. — Canals, whether for navigation, irrigation, 
or drainage, should be shown by double-line symbol only when 
their actual width can thus be indicated on the scale of publica- 
tion; otherwise, by a single blue line. In the mapping of irriga- 
tion ditches mains and laterals are to be shown, the mains to be so 
designated. 

Tunnels. — Tunnels of all kinds, whether on railroads, roads, or 
canals, should be shown by the tunnel symbol; the route of the 
tunnel should be indicated by double broken lines (black for rail- 
roads and roads, blue for canals). 

Dams. — Permanent dams on streams, lakes, or reservoirs should 
be indicated by a heavy black Hne. Where a wagon road follows 
the top of the dam, the road is to be shown in its correct place, the 
road line on the upstream side being thickened to represent the 
dam. 

Reservoirs. — Artificial reservoirs surrounded by dams on all sides 
should not be inclosed by the dam symbol, but should be outlined 
in blue, like lakes or ponds. 

Levees. — Levees should be represented by the symbol. 

Mine dumps. — All mine dumps of sufficient size to deserve map- 
ping should be shown by symbol. 

Wharves, etc. — Wharves, docks, jetties, breakwaters, and similar 
structures should be indicated by heavy black lines with such 
detail as the scale of the mapping permits. 



FEATURES TO BE SHOWN ON MAP. 63 

Lighthouses, etc. — Lighthouses are to be shown by their respective 
symbols and life-saving stations by their name on all maps. 

Cemeteries. — If of sufficient size, cemeteries should be shown with 
their actual outlines; if too small for this, by a square outline in- 
closing a cross. Small private cemeteries should be omitted. 

Mines, quarries, and wells. — ^Maps should show the location of 
all mines, quarries, and wells where considered advisable. In 
sparsely settled regions, where there is little culture to be repre- 
resented, isolated mines, quarries, and even prospects which con- 
stitute important landmarks and are widely known should be 
shown in black with their names. 

Civil boundaries and boundary monuments. — All civil boundaries, 
whether National, State, county, district, civil township, reserva- 
tion (National or State parks, forests, game preserves, Indian, mil- 
itary, or lighthouse), land grants, corporations (city, town, or bor- 
ough), parks, and cemeteries, are to be shown on the map by their 
respective symbols. Special effort should be made by field parties 
to locate such boundaries with accuracy and directly from trian- 
gulation or primary traverse stations, if practicable. 

Necessary descriptions, survey notes, and plats should be con- 
sulted or secured of all lines of importance. Data on National or 
State reservation boundaries should be obtained at or through the 
Washington office prior to the beginning of the field work. Data 
on minor civil subdivisions can best be procured locally while the 
survey is in progress. Many boundary monuments are obscured or 
obliterated by natural causes or artificial works; some are indiffer- 
ently marked to begin with; others have lost some or all of their 
marks. The county or local surveyor or other official should be con- 
sulted in an endeavor to secure a description of the county bound- 
aries by courses and distances, and any information secured should 
be furnished the office. Information from local settlers may often 
prove of value and save time and effort in the search for such 
obliterated lines. The soil man will do well to avail himself of it; 
at the same time he should bear in mind that the word of a resident 
is tiot to be taken as authoritative, but merely as an aid supple- 
menting information from official sources. 

All monuments on National and State boundaries should be lo- 
cated in the field and represented on the map with the appropriate 



64 INSTRUCTIONS TO FIELD PARTIES. 

symbol. On other boundaries it is desirable that monuments 
occupying controlling positions, such as corners or important 
crossings, be located. 

Where lines are found incorrect in azimuth and distance as the 
result of field errors in the original survey, it is a fundamental prin- 
ciple that the line marked on the ground is the de facto boundary 
and is to be shown on the map in its actual position, regardless of 
what the statute calls for. This may necessitate in some cases the 
accurate locating of a number of monuments so each error in the 
alignment may be designated at the particular spot at which it 
exists. 

Some civil boundaries are defined by statute to follow natural 
boundaries, such as streams or divides between watersheds. Those : 
following large rivers should be given special attention, as they 
may be variously defined as following the "middle" of the stream, 
its main current, or one of the banks. 

Public-land surveys.— All public-land survey lines must be shown 
on the soil maps, and to this end it is necessary that a number of 
"corners" on them be accurately located in the field and shown 
on the field map by the proper symbol in red. 

In order to expedite the work of locating corners, party chiefs 
must provide themselves, before taking the field, with copies of 
plats of the land surveys of the assigned areas. These plats should 
be assembled in the form of a combined plat, reduced to the scale 
of mapping, on tracing paper or tracing cloth. A detailed descrip- 
tion of important corners may prove valuable in recovering them. 

The soil man should be familiar with the system of rectangular 
land surveys and the various intricacies peculiar to it. The more 
conversant he is in these matters the more intelligently will he be 
able to make use of land-office data. Acquaintance, further, with 
the standard monuments used for the various classes of land corners, 
their marks, and their bearing or reference trees, as well as with . 
the manner in which blazes on trees become overgrown with bark, I 
will prove most useful both in searching for corners and in deter- 
mining their authenticity where this is in doubt. (For a discus- 
sion of the public-land survey system see Topographic Instructions 
of the U. S. Geological Survey, pp. 183 to 192.) 



d 



FEATURES TO BE SHOWN ON 3IAPS. 65 

Triangulation and monumental primary-traverse stations. — Tri- 
angulation and primary-traverse stations should be located and 
indicated on the soil maps with the open triangle symbol. 

Bench marks. — All permanent bench marks located must be 
shown. 

Black ink should be used to show all cultural features, except 
boundary monuments, triangulation stations, mile posts and other 
points to be used in adjusting and assembling the work, which 
should be shown in red ink. * 

Hydrographic features. — The hydrographic features to be shown 
on the maps are as follows: Shore lines, tidal fiats, tidal (salt) 
marsh, streams — perennial and intermittent, dry stream courses, 
springs, wells, tanks, reservoirs, lakes, ponds, sinks, intermittent 
lakes, dry salt lakes, fresh marsh, and submerged marsh. 

Shore line. — On all maps of the soil survey, the line of mean high 
tide is considered to be the shore line. 

Perennial streams. — The soil man will show on his field sheets all 
perennially flowing streams that the scale of publication will 
permit; to prevent confusion in inking, his field drafting should 
clearly distinguish between perennial and intermittent streams. 

Intermittent streams. — Intermittent streams are those having 
alternating pools and dry stretches, or those flowing for only part 
of the year. 

On the field sheets the field man can not show too much of the 
intermittent drainage. For the engraving, to be sure, only the 
more important drainage courses are to be inked, but for the con- 
struction of the soil map all drainage lines are of value. Often 
they constitute an important element in the local distribution of 
soils and when shown on the map give a fairly good idea of the 
topographic features. Indeed, the systematic tracing out of the 
drainage net can not be too strongly recommended; the earlier the 
traverse man begins to cultivate the habit, the more successful he 
is likely to be in his work. 

Disappearing streams. — Many streams in limestone regions 
abruptly sink into caverns and continue their courses for long dis- 
tances through subterranean channels. Special care should be 



66 INSTRUCTIONS TO FIELD PARTIES. 

given to the mapping of this type of drainage; the points of dis- 
appearance and reappearance should be accurately located. 

Springs. — The importance of springs is dependent pn their 
relative usefulness as a part of the water resources of the region in 
which they occur; and that is the criterion that should govern 
their mapping. Thus, although it would be entirely proper to 
omit springs in large numbers from maps of well-watered regions, 
it would be manifestly improper to leave them off from any map, 
even the merest reconndissance, of desert regions. 

Wells and tanks. — The importance of wells and tanks, like that 
of springs, depends entirely on their relative usefulness as a part of 
the water resources of the region. In semiarid regions both wells 
and tanks must be shown. Wells, if artesian, should be so desig- 
nated . 

Map the actual distribution of water at the time of surveying it. 

Fresh-ivater marshes. — All fresh marsh and swampy areas occur- 
ring in soil types should be shown on the field map with fresh- 
water marsh and swamp symbols. 

Submerged marsh. — Marsh lands that are partly submerged for 
many months each year are to be differentiated from ordinary 
marsh and represented by a special symbol combining water and 
marsh tufts. 

All hydrographic features should be shown in blue ink. 

Names to be shown. — The map should show the names of: Cities, 
towns, villages, and other settlements, including all country post 
offices and railroad stations,^ country schoolhouses, country 
churches, isolated ranches constituting important landmarks in 
sparsely settled districts, important public institutions, such as 
universities and colleges, State hospitals, asylums, and peniten- 
tiaries. Steam or electric railroads, ^ highways, turnpikes, boule- 
vards, bridges, ferries, fords, through trails, important steamboat 

JWhere the name of a railroad station differs from that of the corresponding 
post office, both names should be shown, the one most widely known being given 
the greater prominence and the other being followed by P. O. or Sta., as the case 
may be. 

2 In addition to the name of the system, it is desirable, as a rule, to give the name 
of the branch, line, or division. 



INSTEUCTIONS TO FIELD PARTIES. 67 

routes on large lakes, important canals, ditches, aqueducts, tunnels, 
dams, lakes, reservoirs, and other public works; lighthouses, and 
live-saving stations; parks and cemeteries; isolated mines, quarries, 
prospects, and oil wells; isolated furnaces and smelters; civil divi- 
sions; reservations; hydrographic features; springs, wells, and tanks, 
especially in arid regions where these features are of vital impor- 
tance; and all relief features. 

Authority for names. — The soil man should utilize local opportuni- 
ties for obtaining the correct names and spelling of all features 
shown on the map and not resort to correspondence on this subject 
after his return to the office. The general policy should be to 
conform to local usage. 

IDENTIFYING AND MAPPING SOILS. 

Being provided with a suitable base map or with the knowledge 
and facilities for the construction of a base map, it now remains to 
describe how the soils are to be identified and mapped. The 
identification of a soil does not presuppose its mapping and may 
be done without reference to a base map. The determination of 
its distribution, however, is wholly geographic, and to show the 
distribution accurately it must be projected upon a reliable base 
map. The delineation of soil boundaries on the map may be 
done during the progress of basE-map making and by the same man, 
in which case he performs three distinct functions : (1) The making 
of a base map, (2) the identification of soil units, (3) the delinea- 
tion of soil boundaries. If he is furnished with a reliable base 
map he performs only the two last-named functions. 

The identification of soil units or types in the area is based upon 
the general character of the soil and subsoil material, the general 
character of the topography and the physiographic situation, the 
source or derivation of the material, and the agencies through 
which the material has been accumulated. 

The principal soil and subsoil characteristics to be determined in 
the field are: Color of soil and of subsoil^ — to a depth of 3 feet in 
the humid region and 6 feet in the arid regions, noting any change 
with increasing depth ; texture of the soil and of the subsoil, noting 
such variations as occur in increasing depths; structure of soil and 



68 INSTRUCTIONS TO FIELD PARTIES. 

of subsoil material; drainage conditions of soil and subsoil, and 
any marked chemical or mineralogical features. 

The principal topographic and physiographic features are: 
Valleys, mountains, plateaus and plains, terraces, former lake 
beds, and river flood plains. 

The principal sources or origins of material are: Granites, 
gneisses and schists, basalts and other quartz-free rocks, slates and 
phyllites, sandstones and shales, limestones, and mixed rock 
material. 

The principal processes of accumulation of soil material are: 
Residual, from consolidated rocks; ice-laid, water-laid, and wind- 
laid. 

Examination of the Soil Material. 

In the work of identifying soils it is necessary to examine the 
material from the surface downward through a vertical section of 
3 to 6 feet — 3 feet, as a rule, in the humid region and 6 feet in the 
arid region. Sometimes it is advisable to make examinations to 
greater depths in order to study the substratum conditions which 
may have some special bearing upon the present or future worth of 
the soil, as, for example, to determine the depth to and altitude of 
a gravel bed in its relation to drainage, or, if in the arid West, to 
detect alkali or a heavy impervious layer which might arrest 
drainage to such an extent as to cause accumulations of water or 
alkali at the surface at some future time after irrigation has been 
introduced. 

Examinations of the soil material are usually made with an inch 
and a half wood auger, which is provided with extra couplings, so 
that it can be extended to any desired length, and from which the 
cutting side flanges and the bit have been removed. (See fig. 21.) 
Borings are made by holding the auger in a vertical position and 
bearing down on it and turning it until the point has penetrated the 
ground to a depth of 2 or 3 inches. On pulling the auger out, a 
section of the soil material comes out on it in much the same con- 
dition as it existed when in place. The process of boring a few 
inches out at a time is repeated until the desired depth of 3 feet, 
6 feet, or more is reached. 



p:xamination of soil material. 



69 




To ascertain the character of and variations in the material from 
the surface downward it is necessary to bore only a few inches at a 
time, not to exceed 6 inches in even the lighter soils, for the reason 
that important changes of color and other characteristics are other- 
wise liable to be overlooked. It is very essential that all variations 
in color, texture, and structure, 
and the occurrence of other prop- 
erties within the 3-foot or 6-foot 
section, as the case may be, should 
be carefully studied and note 
made of them. 

Frequently it is desired to 
examine only the surface mate- 
rial to determine its color, text- 
ure, or structure. In such cases 
a modified form of geologist's 
hammer may be used to good 
advantage (fig. 22). The hammer 
also is preferable to the auger in 
examining very stony soils, and 
comes in handy in examining rocks 
from which the soil material is 
derived. 

It must be remembered that 
the soil auger is an instrument 
for revealing the character of 
material below the surface which 
makes up the general character- 
istics of a soil. The number of 
borings that must be made in any 
given area must be left to the 
discretion of the field man, as the necessity for these borings de- 
pends upon the complexity of the soils of the area. In an area of 
obviously uniform soil conditions borings may be widely scattered. 
In an area of very complex soil conditions, and especially along the 
boundary lines, borings must often be very frequent. Often 
slight depressions or elevations, a change of the color of the surface 
material, or a change of the character of the surface or of the vegeta- 
tion will indicate to the experienced soil man a change of soil 



Fig. 21.— Soil auger. 



70 



INSTRUCTIONS TO FIELD PARTIES. 



conditions to be investigated or verified by an examination with 
his soil auger. 

At least one typical sample of siil and subsoil of each soil type 
must be sent in to the bureau from each area, and the sample so 
selected must be taken by the soil auger filling the sacks from the 
material adhering to the auger when it is drawn up. When the 
need is felt by the soil man to take samples of phases or of peculiar 
soil material, he should plainly indicate upon the label that 

such samples are sent in for special 
examination and that they do not 
represent the type as a whole. He 
should also state the character of ex- 
aminations desired upon the label, 
and more fully describe them by 
letter. 

In collecting samples care must 
be taken to put into separate sacks 
material differing in color, texture, 
or other observable feature. The 
bureau needs but one representative 
sample of each soil type to serve as 
a basis of comparison for correlation 
purposes. All variations from this 
typical material observed in the 
numerous borings that are made shall 
be entered and described in the note- 
book and sent in to the bureau in this 
form for the information of the cor- 
relation committee, but without ac- 
companying samples. 
Borings, to determine the characteristics of the soil, should not 
be taken in mere spots, where the soil may represent some unim- 
portant local variation, such as is frequently found in slight de- 
pressions, on eroded slopes, and in situations where colluvial 
material has accumulated. To get the type characteristics, a place 
should be selected in which the soil is representatively developed. 
The local variations, which are unmappable on the scale used, 




Fig. 22.— Ceolo.2;ist's hammer. 



EXAMINATION OF SOIL MATERIAL. 71 

should, of course, be examined and descriptive notes taken, so that 
such variations can be carefully described in the report. 

While it is important to study soil sections, particularly the sub- 
soil and substratum in road cuts, wells, and other exposures, it is. 
generally not advisable to consider the sectional characteristics of 
such exposures as representing the sectional features of a type, since 
frequently the soil section in such places is shallower than is 
characteristic of the type, and the face of the section may be 
discolored or otherwise modified by material of colluvial creep. It 
is always best to take a type description from borings made at some 
distance from exposed sections and from minor slopes and de- 
pressions. 

All borings made in the progress of the soil survey in establishing 
the character or distribution of a soil type should be carefully noted 
in the field book and the location from which the typical sample 
sent to the office is taken should be indicated on the base map 
by a small letter "s." The notes in the field book should indicate 
by inches, in the vertical section, any important difference of 
color or shade of color, and any important differences in texture, 
structure, rock or gravel content, and drainage condition. These 
notes should refer specifically to the soil, the subsoil, or to any sub- 
stratum. 

For the purposes of soil classification and description the soil 
type refers to the entire section from top to bottom, including the 
top soil, the subsoil, gravel beds, layers of hardpan, or a substratum, 
upon which the subsoil rests. For the purpose of describing the 
soil material of any soil type it is customary to refer to the soil, 
meaning the soil proper or the top sdII as a layer distinguished from 
the subsoil. The distinction between soil and subsoil has never 
been clearly defined, and in some cases the distinction between 
the two is difficult to see. If the 3-foot soil section has the same 
color, texture, and other physical peculiarities throughout, it is 
proper to refer arbitrarily to the upper 6 or 8 inches as the soil and 
that below this as the subsoil. Usually, however, there is either 
a change of color or a change in texture between 5 to 20 inches 
below the surface; and where this upper partis uniform throughout, 
but differs in some important physical characteristic from the 

42126—14 4 



72 INSTRUCTIONS TO FIELD PARTIES. 

underlying material, it is referred to as the soil, while the under- 
lying material is referred to as the subsoil. Occasionally it is 
found that the soil material may have two layers differing slightly 
in color or in texture, and it is frequently found that the subsoil 
consists of layers differing in color, texture, structure, or drainage 
peculiarities. 

Color. — In identifying soils color is of prime importance, being 
not only one of the most conspicuous features but reflecting phys- 
iological and chemical differences, as in the amount of the organic 
matter and of minerals which are or may be made of determining 
agricultural importance. Color as used in classifying and describ- 
ing soils does not refer merely to the surface coloration as viewed 
across a field, but to the color of the soil as deep as it extends, and 
of the subsail to a depth of 3 or 6 feet. What should be considered 
as the true color of the S3il, or of the subsoil, is that which it pos- 
sesses when bored out moist for examination; in other words, the 
color it has under normal field conditions. 

As the color of the soil material is dependent upon or influenced 
by weathering, drainage, amount and character of urganiv, -matter 
content, exposure, and cultivation, besides the mixed origin of 
material and a slight predominance of one material in certain places, 
it is not to be expected that the color of a soil will be uniform 
throughout its whole expanse. It is to be expected, on the other 
hand, that variations will occur. An effort to show the true place 
of a soil in a color scheme is all that can be accomplished, but in 
doing this, if it is attempted to give all detailed variations, con- 
fusion results and no good is accomplished. The principal soil 
colors are: A^Tiite, black, red, yellow, gray, and brown, with shades 
and variations produced by different combinations, particularly 
of the yellow and red. The entire scheme of soil classification in 
the province keys of Bulletin No. 96 has been worked out prac- 
tically under the following color scheme: AATiite, black, gray, 
dark gray, light gray, yellowish gray, drab, yellow, reddish yellow, 
red, Indian red, chocolate red, pinkish red, purplish red, light red, 
dark red, brick red, brown, light brown, dark brown, reddish 
brown, and chocolate brown. Such other colors as green and blue 
very rarely occur, although these and other colors and other shades 
are occasionally found, and when found should be stated. 



EXAMINATION OF SOIL MATERIAL. 73 

In other words, it has been found sufficient for purposes of soil 
classification and as the result of a vast amount of work done by the 
bureau to give certain distinctive class colors as the characteristic 
color of the type, and it has been found to be simpler and more 
satisfactory not to confuse this in the main color description by 
attempting to show the variations of color that may be exhibited 
by the soil type under different conditions of exposure and use. 
The Portsmouth series is properly described as a series of black 
soils, indicating that it belongs to a class of black soils. This dis- 
tinguishes it at once from the associated Norfolk series, which is 
properly described as having a gray soil and a yellow subsoil. 
The Portsmouth series, however, throughout all its extent is not 
literally black. It may, under exposure and good drainage con- 
ditions, or when air dry, or with local accumulations of material, 
become much lighter and grayish in color. It must be remembered, 
however, that color is but one of the characteristics of a soil, and 
color may vary within limits without changing the ultimate classi- 
fication of the soil material. The Cecil clay has a subsoil which 
is properly described as belonging to the class of red soil material. 
It is not always the same shade of red, but it is never a decided 
Indian red, as is the subsoil of the associated Penn series, nor has 
it the yellow color of the subsoil of the associated York series. 

It will be sufiicient, therefore, for the field man to determine 
from observation the color class, and while he should make notes 
of the variation in the different phases presented in the field, the 
ofl&cial color designation of the soil material must represent the 
general or predominating color that is presented to him in the ex- 
amination of the soil as a whole. 

The color of a soil type is usually made up of two parts, the color 
of the surface soil material and the color of the subsoil material. 
Usually the color of the surface soil differs from the color of the 
subsoil material. Occasionally they are the same, and occasion- 
ally the subsoil is made up of layers of two or more differently 
colored materials. All such variations as this in the vertical sec- 
tion must be given, but each color so described must be a class 
color referring to that particular section of the profile as distinctive 
for the soil type as a whole. 



74 INSTRUCTIONS TO FIELD PARTIES. 

As the samples sent in to the office for the use of the correlation 
committee are usually in an air-dry condition, imposing certain 
changes or modifications of color, it is important, to avoid misap- 
prehension and confusion in comparing the color of the air-dry 
sample with the field color, for the field man to state the color of an 
air-dried sample in the condition it would be handled by the com- 
mittee to enable the committee to judge fairly of his interpretation 
of color in any particular case. 

It occasionally happens, as in the Guin series, where for some 
local reason during the accumulation of the deposit, materials of 
different origin, in this case, Orangeburg, Ruston, Susquehanna, 
and Norfolk material, have been brought together and not thor- 
oughly mixed by the transporting agent, or when uniform weather- 
ing of the material has not occurred. The resulting soil material 
is so mixed and variable as to make it impossible on the scale of 
map used to differentiate the different classes of material. A 
series name is chosen to represent the series as a whole, and in 
this case a color description of the soil would properly be given as 
red, yellow, and gray, with an explanation that these color classes 
are variable because of variations in the material which it is 
impossible to outline on a map of the scale used. 

In other cases, as in the northern extension of the Susquehanna 
series, there may be a marked variation of color occurring over a 
very small area, due to beds of material a few inches thick lying 
either in a vertical or horizontal position with markedly different 
colors. In this particular series it is not infrequent to find within 
10 or 15 feet alternate beds of clay and sand, and alternating colors 
of brilliant red, deep black, bright yellow, white, and blue, and 
such conditions can only be described as variable color of white, 
red, blue, and yellow, as the case may be. 

In other cases more frequently found, where drainage is deficient, 
the color, owing to slight differences in drainage and aeration, 
changes from red to yellow or gray in a single hand specimen 
This condition is properly described in classification as mottled 
with red, yellow, or gray or other colors predominating, as the 
case may be. 

Texture. — The texture of the soil material is determined in the 
field by rubbing small samples between the thumb and finge: 



\ 



X gA 



EXAMINATION OF SOIL MATERIAL. 75 

in the palm of the hand. The range of texture arbitrarily adopted 
by the bureau divides the material into 12 different classes, namely, 
coarse sand, sand, fino sand, very fine sand, sandy loam, fine sandy 
loam, loam, silt loam, sandy clay, clay loam, silty clay loam, and 
clay. These are determined by the different admixtures of dif- 
ferent grades of ^ sand with silt and clay, and are determined 
accurately and finally by mechanical analysis in the laboratory. 
The official classification of material constituting each of the above 
grades is contained in the following table: 

Classification of soil material.^ 

Soils containing —20 silt and clay: 

Coarse sand 25+ fine gravel and coarse sand, and less than 

50 any other grade. 
Sand .25+ fine gravel, coarse and medium sand, 

and less than 50 fine sand , 
Fine sand 50+ fine sand, or —25 fine gravel, coarse and 

medium sand. 

Very fine sand 50+ very fine sand. 

Soils containing 20-50 silt and clay: 

Sandy loam 25+ fine gravel, coarse and medium sand. 

Fine sandy loam 50+fine sand, or— 25 fine gravel, coarse and 

medium sand. 

Sandy clay 20 silt. 

Soils containing 50+ silt and clay: 

Loam —20 clay, —50 silt. 

Silt loam —20 clay, 50+ silt. 

Clay loam 20-30 clay, —50 silt. 

Silty clay loam 20-30 clay, 50+ silt. 

Clay 30+ clay. 

1 The sizes of the particles of the different grades adopted by the bureau and used 
in the mechanical analysis work are as follows; 

Grade. Millimeter. 

Fine gravel 2 to 1. 

Coarse sand 1 to 0.5 

Sand 0.5 to .25 

Fine sand 25 to .1 

Very fine sand 1 to .05 

Silt 05 to .005 

Clay 005 to .0001 

2 The figures in this table represent per cent; the minus sign (— ) and the plus 
sign (+) represent less or more: and the sign (-) when used between two figures, 
thus, 20-50, giving limiting values, should be read from 20 per cent to 50 per cent. 



76 i\sTnr( rioNs to viyaai parties. 

Care must be exercised in jiid^iiiy 1]ie texture of the mineral 
material in the i)resence ( f a e()nsi(h'ral)ie aiunuut of organic matter. 
The presiMK (' of rock fra^u'iueuts or of _t,^i-a\('l. wliere important as 
alYectiu!^ cultivation or mo(lifyin<j: drainai^e. should he indicated in 
1.1ie ty])e name l)y prefixing the character <'f t.he material thus: 
Stiny lii)m. gravelly ham. shale 1< am. 

The texture of siil material is \i>^vd l)y tlie hureau to ap])]y to the 
))articular sample of material witliout r( gard to the proximity of 
material of any other texture; hut tlie t^'Xture (^f a s;iil ty])e refers 
to tlie upper soil, as modilied hy the texture of tlie .--nhsoil ma'erial. 
.\ sandy h-am type may liav(^ a sandy loam textnre thronghont the 
:\ or (i foot section. On the other liand. a .^andy loam ty{)e may 
have a sandy to]) soil and clay suhsoil, t)ie comhination liaving 
approximately the same physical ( haracterist ics as the other as 
regards Avater-holding ca])acity. ^v)lich is one i f the most important 
pro])erties of tlie class of soil from an agricullnral standpoint. In 
general, the cla.ss to whicli a soil 1\']h' lielougs is defined by the 
texture of tlie surface s;iil to a depth of 5 to 10 inches. ])rovided that 
the material to this depth lias Ix-eii or will l>e thoronglily mixed 
through ordinary metliods of cultivation. 

(Jeiieially the surface soil is lightei' in texture: that is, it has less 
fday and more s;ind than the suhsoil. if a change of texture comes 
within L' oi' :•) inches of the sui'face, it may generally be neglected 
as it is likely 1(» ha\-e little significance, esjx'cially with thorough 
cultivation; hut when the change in textui'e comes at a dej)th of 
S to 10 imdies, it is likel>- to be (|ui1e signilicani and must be con- 
sidered. l''or example, the Cecil clay has noiimdly from MO to 50 
per cent of claw but ne;irly alwa\s in a Aurgin state it has 1 or 2 
in(dies of sandy material as a surface co^-er which has lieeii left as 
a result of su|)erlicial <'rosion. ihit when this sandy layer is (i to 12 
inches thick with the (d;i\- immediately underneath, the type 
becomes the Cecil sandy loam because when plowed it will still 
retain its sui-f;u'e sandy texture. 

Th" detei'inin:ition of the (d:iss to wliich a soil helongs in a series 
must rest upon the judgment of the li<dd man conlirmed by the 
judgment of the inspector who \ lews his work, as the mechanical 
analysis when made can only conhrm his judgment as to the tex- 



EXAMINATION OF SOIL MATERIAL. 77 

ture of any particular part of the 3-foot section, and there is no 
known method of measurement to determine into which class a soil 
as a whole which differs in texture in vertical section belongs. 
The field man may be guided, however, by the fact that there ia 
always a similarity running through every soil series. Every 
member of the Cecil series invariably has a clay subsoil. And 
furthermore, when he describes a type as a sandy loam or as a silt 
loam or as a clay, he invariably describes the actual texture of the 
soil and of the subsoil separately and notes other differences in 
-texture that are observable within the 3-foot or 6-foot section. 
These characteristics go to make up the full soil section and are 
capable of confirmation by mechanical analysis. 

Structure. — When a sample is taken by means of the soil auger 
-for the determination of color and texture the field man will also 
determine and make notes upon the structure of the material. 
The structure has a very marked influence upon ease of cultivation 
and the requirements of tillage operations and also upon the water- 
holding capacity and drainage of the soil. It is important, there- 
fore, that the field man state from his field observation whether the 
material is loose and porous or compact and impervious. If any 
portion of the soil section is a clay, it should be determined whether 
this is a friable clay, a plastic cjay, or a stiff clay. It may often be 
necessary to see the soil under both dry and wet conditions, or to 
bring about these conditions by wetting the sample or drying it. 
If the soil material has a granular structure, or, in the case of sd,nd, 
if it has a loamy consistency as compared with a loose and incoher- 
ent sand, this should be stated. A silt loam may present the 
appearance of floury material, such as the Memphis soils, or it may 
have an exceedingly compact and impervious structure as the 
Lufkin soils have. Soil material may exhibit a stickiness which 
causes it to adhere to the auger or to the hand, or it may be of a more 
pulverulent nature with the absence of a sticky character. Certain 
clays are distinctly gritty; others are smooth and unctuous and 
readily puddled if handled in a moist or wet condition. The adobe 
structure is a striking characteristic of certain soils, particularly in 
arid regions, and may be exhibited through the range of soil classes 
from sandy loam to clay. Certain soils like the Manor soils of the 



78 INSTRUCTIONS TO FIELD PARTIES. 

Piedmont Plateau derived from liiglily micaceous rocks exhibit a 
smooth, greasy feel when rubbed between the fingers. This is due 
to the presence of a mass of exceedingly fine mica flakes. All such 
structural peculiarities as this associated with the soil material are 
liable to have an important bearing upon the economic use of the 
soil. 

Not infrequently there will be a compact layer encountered 
immediately below the zone of cultivation, locally known as hard- 
pan, but without any definite cementing material, the compactness 
of the layer depending upon artificial pressure along the same hori- 
zontal plane. This is more frequently encountered where a single 
cropping system prevails and where the plowing has been shallow 
and approximately of the same depth. 

Frequently, however, there are layers of true hardpan encoun- 
tered at lower depths in the subsoil material. These have resulted 
from the cementing of soil grains by lime carbonate — in which case 
it is called a calcareous hardpan — or by iron material — ferruginous 
hardpan — or by silica itself, in which case the material is truly 
stonelike in appearance. Frequently these hardpan layers form at 
or near the junction where marked change in texture occurs. 
Sometimes an unbroken layer of hardpan underlies extensive 
areas. Occasionally there is encountered a layer of sand in the 
subsoil the grains of which are so rounded and saturated with water 
as to have the properties of a quicksand. Frequently these struc- 
tural peculiarities are sufficient to constitute differences between 
soil series. In all soil examinations careful notes must be taken of 
these or other structural peculiarities, and their existence and effect 
on the value of the land pointed out in the description of the soil 
type. 

Drainage. — The examination of the soil material should include 
the relation of the material to drainage. Where the surface soil or 
any portion of the subsoil shows lack of drainage the fact is usually 
apparent, upon boring into the soil, from the excessive amount of 
water encountered, but consideration should be given of course to 
the climatic conditions which have prevailed at the time the 
examination is made. In a very wet season the soil material may 
exhibit an unusually high water content, much higher than the 



EXAMINATION OF SOIL MATERIAL. 79 

normal. In an exceptionally dry season, the soil material may 
show an amount of water abnormally low. The field man must 
judge of this from his experience and from seeing the soil under 
such different climatic conditions, as his stay in the area will permit, 
but in all cases he will be helped in his judgment by topographic 
and physiographic relations, by textural and structural conditions 
of the soil, by the color of the soil, and frequently by the mottling 
of the subsoil, as well as by the kind and condition of native vege- 
tation or of cultivated crops. 

The drainage conditions as affected by physiographic position, 
as this is expressed in the first bottom, or a second terrace, or a high 
terrace, is recognized as an important factor in determining the 
soil series. The drainage condition also has much to do with the 
functioning of soils and often marks their relative age as soil mate- 
rial. On areas of swamp the soil is yet forming. On better drained 
first bottom lands a more mature age of material, which often lacks 
distinctive soil character, is represented. The second bottom is a 
young soil in which the functional activities have really been estab- 
lished, where the assortment and mixing of material is complete, 
and where the circulation of water and air is normally expected to 
have become established more nearly as in an old soil. The old 
high terrace marks an advance in age, possibly to the extent of 
excessive drainage and excessive aeration, or even excessive ero- 
sion, which may mark the beginning of a decline in natural pro- 
ductivity. It is believed that the essential difference between 
the Portsmouth, Norfolk, and Orangeburg series is due to physio- 
graphic changes that have taken place, the maturity of the func- 
tional activities ojjrthe soil material with resultant changes in the 
amount and condition of the organic matter and of ferruginous 
material. 

The drainage condition of the soil material is therefore at times 
a very important factor in the classification of soils, as well as an 
indication of the cultural requirements. 

Marked chemical or mineralogical features. —Attention should be 
called by the field man to any marked chemical or mineralogical 
feature of the soil type. Reference has already been made as to 
the necessity for distinguishing between the different forms of 



so INSTrHJLTXOXS TO FlEIj):) PARTXKS. 

liar(l]);ui, Tlio (KTurronco of liii^hly i'crrii,<i'inoti.s matorial either 
distributed tliroiii^h the soil or in tlie form of concretions or accre- 
tions on or near the surface, or the occurrence of tlie green mineral, 
,i:;hiuconite, should he noted. The i)resence of unusual amounts of 
(hirk-colored iron or titanium miner;ils, the ])resence of unusual 
amounts of mica or of ([uartz or of feldspar, tlie ])resence of ,u-y])sum 
or of iron ])yrit(\s, or the occurrence of alkali salts, tlie methods for 
dcterminin,L;- Avhich will \h\ uiven in a sc])arate chapter, should be 
noted. The pr(>sence of considerable calcium carbonate as revealed 
by the acid test should be noted. The presence of marked acid 
conditions as determin(Ml by the litnuis-])ai)er test should be 
reconkxL All such marked chemic-al or mineralngical features 
should be stated and if necessar\- their ])resence confirmed by 
lalx )rat ( >ry examinat i( )n . 

TorOCKAPHY AND PuYS10(!KArHlC SiTUATIOX. 

While the bureau does not attempt to map topography, it is im- 
])ortant that the iieldnian should fake advantage of all tojjographic 
ma|)s or consider b)j)ogra])hy in its relati(m to soil maj)])ing. It is 
l)arlicu]arly important, however, that he give careful attention to 
the topogra])hic situation, as thiswill often help him to determine 
the source of the material and the agencies through which the 
material has accunuilated. It is im])ortant, also, in his description 
of the area and for tlie ])roper understanding of the soil relation that 
t he general physiograi)hic features of the area be described, whether 
in the main or in any ])art of the area, the surface presents the gen- 
eral features of a A'alley, a ])lateau, a phiin, or a rough or even moun- 
tainous condition. Such information not only leads to correct 
classilication of soil material and of soil types, but it may have 
nuich to do with the ex])lanation of the ])resenl or future use of the 
.•<oil type. 

SoriicK AND Dkkivathjx of Material. 

To insure the ])roper classification of soils it is important to know 
tlie (h'rivation of the material. Soil material derived directly from 
the disintegration of granite, talcose schist, ba.^alt, and other 
• piartz-free minerals, limestone, and sandstone have essentially 



SOURCE AND DERIVATION OF MATERIAL. 81 

different properties, the reason for which may not be well under- 
stood though the facts upon which to base the classification may 
usually be determined. In the case of residual soils derived 
directly from the weathering and disintegration of solid rocks, the 
important guides are: Exposures of the rock itself at the surface or 
in road cuts, the evidence presented by geologic surveys and maps, 
the physiographic relationships, and the character of the soil mate- 
rial itself. In case of heterogeneous material which has been 
transported by ice, a study of the rock content of the soil or subsoil 
will often reveal the main character of the material from which the 
soil has been derived. Granitic material, sandstone and shale, 
limestone or basalt fragments will appear in such form and fre- 
quency as to give a fairly correct idea of the original source of the 
material. 

In the case of soil material transported by running water or by 
waves in lakes or oceans, the general source of the material may be 
obtained by studying the physiographic position with reference to 
drainage basins and noting the course the material must have fol- 
lowed from its source to its present position. The material of the 
northern extension of the Coastal Plain must have been derived 
from the Piedmont, Appalachian, and Limestone Valleys provinces 
through the Potomac-Delaware-Susquehanna drainage, supple- 
mented by a fraction of glacial material brought in through the 
Susquehanna and Delaware drainage ways. From the Potomac 
River to the vicinity of the Mississippi- Alabama line the Coastal 
Plain material must have been derived from the Piedmont Plateau 
and the Appalachian Mountain region and the Limestone Valleys, 
without admixture of glacial material because of the peculiar 
physiographic relationships that exist. In portions of Mississippi 
and Louisiana, built up by the Mississippi River, the Coastal Plain 
material is derived probably to a considerable extent from the 
glacial and loessial material through which the Mississippi River 
and its principal tributaries flow. The material in the extreme 
western part of the Coastal Plain, as developed in Texas, is derived 
principally from the shales and sandstones of the Great Plains 
region brought in through the drainage basin of the various streams 
which head in that region. 



82 INSTRUCTIONS TO FIELD PARTIES. 

Agencies Through Which Material Has Accumulated. 

Having determined the saiirce of the material, it remains to de- 
termine the principal agencies through which the material has 
accumulated. The agencies recognized by the bureau as essen- 
tial in the classification of soils are few and in the main are readily 
determined, though sometimes they are obscure and, particularly 
along boundary lines, may be difficult to determine. The first of 
these is: The weathering and disintegration in place of consoli- 
dated rocks without material subsequent movement or mixture 
except through local creep and erosion, giving rise to residual 
material. The next is the agency of moving ice and the influence 
of the rushing glacial waters as the ice recedes. The evidence of 
ice-laid accumulations is usually to be seen in the more or less 
stony and unsorted character of the soil or subsoil material. The 
evidence of ice-laid material subsequently acted upon by rushing 
glacial waters is sometimes more difficult to determine but is usu- 
ally indicated by a broad separation of coarse residual material, 
flanked by plains or filled-in valleys of sand with outer zones of silt 
and clay. The stratification of the material as seen in the vertical 
section is also an important criterion. The next important agency 
is the wind, which has a tendency to mix materials from widely 
separated localities. This influence is felt more or less in all soils, 
but becomes sufficiently marked to serve as a basis for soil map- 
ping in only a few definite areas. The principal evidence of wind 
deposition is the great uniformity in the character of the material, 
the fact that the body covers both hills and valleys with a blanket 
of comparatively uniform thickness, or that it has the form of 
dunes or hillocks. 

The remaining agency to be mentioned is water transportation 
by river and wave action. Water-laid deposits will reveal their 
manner of accumulation through the stratification of the material, 
which will be nearly horizontal, and by a smooth and practically 
level original topography. The stratification of the material can 
usually not be seen in the upper 3 feet of the deposit because of 
the influence and effects of roots of plants, animals, cultivation, 
and soil creep. Soil material transported through the agency of 
running water is very different from the same material that has been 



ELEMENTS OF SOIL CLASSIFICATION". 83 

subjected to the influence of wave action or ine distribution and 
segregation of the different grades of material through ocean or 
lake currents. 

Elements op Soil Classification. 

Soil provinces. — To aid in the classification of soils the United 
States has been divided into seven soil provinces east of the Great 
Plains regions and into six soil regions covering the Great Plains 
and the country lying between it and the Pacific Coast. ^ The soil 
province is an area in which the main agencies of accumulation are 
similar, although to a slight extent topography and origin of ma- 
terial have been recognized. The Piedmont Plateau Province is 
an area where the soils have been derived directly from the dis- 
integration of the old crystalline and metamorphic rocks. The 
Appalachian Mountain and Plateau Province includes a region of 
peculiar physiographic form in which the soil material has accumu- 
lated mainly through the disintegration of sandstone, shale, and 
interbedded limestone. The Limestone Valleys and Uplands 
Province includes those regions in which the soil material has 
accumulated from the disintegration and solution of moderately 
pure limestones of broad extent. The Glacial and Loessial Prov- 
ince includes those areas in which the soil material has accumu- 
lated through the agencies of moving ice modified to some extent 
locally by the rushing sheet waters at the front of the receding ice 
mass, and deposits formed by wind. The Eiver Flood Plains 
Province includes those areas in which the material has been or 
is now being deposited by rivers and smaller streams. The 
Coastal Plain Province includes the vast areas formed by material 
transported by streams into the ocean or along the ocean front, 
subjected to wave and current action with considerable separation 
and segregation of material, and subsequently elevated to form 
land. The Glacial Lake and River Terrace Province includes 
those areas occupied by glacial material that has been reworked 
and sorted out by wave and current action of the old glacial lakes 
and rivers, which have now largely disappeared. 

1 The provinces and regions are shown on a map accompanying Bulletin 96, 
Bureau of Soils. 



84 INSTRUCTIONS TO FIELD PARTIES. 

The soil regions of the western part of the country are separated 
on the basis of physiographic, geologic, and climatic differences. 
The Great Plains Region, the Rocky Mountain Region, and the Great 
Basin Region represent different physiographic areas. The Arid 
Southwest Region represents both a physiographic and a climatic 
region. The Northwest Intermountain Region represents i)artly a 
physiographic and partly a geologic condition, while the Pacific 
Coast Region represents a physiographic or geographic region. In 
any one of these soil regions one or more of the soil-forming agen- 
cies may be found: thus, in the Great Plains Region there are 
soils derived directly from the disintegration of sandstones, shale, 
and interbedded limestone; there is soil material resulting from 
the transportation and deposition of material by moving water; 
there is material vrhich has accumulated by moving ice; and there 
is material that has accumulated through wind transportation and 
deposition. The classification into soil regions rather than into 
soil provinces is justified on the substantial difference in climate 
prevailing over the eastern and western halves of the United 
States and its influence upon soil character. It has also resulted 
from the more limited knowledge of soils, geology and physio- 
graphic relations in the western part of the United States. 

Soil series. — ^The soil province takes into account only the broader 
relation of soils as regards their general origin and mode of accumu- 
lation and marked differences in physiographic features. The 
soil series goes a step farther and brings together all soils, in any 
one province, that have the same range of color of surface soils and 
of subsoils, the same relative character of subsoil material, partic- 
ularly as regards structure (with exception of the deep sand mem- 
bers), the same general character of reUef and drainage, and a 
common or closely related origin as to source of material. In each 
of the provinces the bureau has recognized a number of well- 
defined series, which are arranged and described in the text and 
keys of Bulletin 96. 

The soil series, therefore, represents material of uniform char- 
acter, origin, and mode of formation, except that it will contain 
material of different texture. This variation in the texture of 
otherwise identical or closely related material gives rise to the unit 



MAPPING SOILS. 85 

of soil classification, the soil type. The soil series are designated 
by the use of local names of towns, counties, rivers, etc., usually 
selected from the locality where first encountered. Illustrations 
are the Norfolk series, the Fresno series, and the Wabash series. 

Soil type.— The soil type is the individual member of the soil 
series based upon the difference in texture, arranged arbitrarily 
into 12 classes — namely, coarse sand, sand, fine sand, very fine 
sand, sandy loam, fine sandy loam, loam, silt loam, sandy clay, clay 
loam, silty clay loam, and clay. 

This descriptive class term when added to the series name gives 
the name of the soil type and shows its place in the soil series. 
Thus we have the Hagerstown sandy loam, the Hagerstown silt 
loam, and the Hagerstown clay, indicating three classes of Hagers - 
town material and three types or members of the Hagerstow*n 
series. Differences not sufficient to justify a new series, such as 
slight differences in character of material and drainage, important 
variations in topography and depth of soil, the presence of hardpan 
and important differences in native vegetation, may be expressed 
in the mapping of soils as a phase, using the same color with con- 
ventional sign or symbol to indicate the phase, the basis for the 
recognition of a phase being given in the report. 

Mapping Soils. 

Soil mapping consists of outlining upon a base map the area and 
distribution of different types of soils. Unlike the construction of 
a base map, the boundaries of the soil type are usually not trav- 
versed but positions are determined with reference to cultural fea- 
tures, such as landlines, roads, cross roads, railroads, and houses, and 
to topographic and physiograj)hic features, such as hills, valleys, 
and streams. In starting on the survey the field man, through a 
sufficient number of borings, becomes acquainted with the char- 
acter of the soil type and proceeds with caution and judgment 
until the character of the soil material changes to another soil 
type. If the change in character of material from one type to the 
other is sharp and distinct, as is usually the case with any marked 
change in topography or physiographic position, the point of con- , 
tact can be accurately located with respect to the nearest cultural 



86 IXSTEUCTIOXS TO FIELD PARTIES. 

or physiogi-aphic feature shown upon the base map. If one tj'pe 
merges gradually into another, the line of separation is less easily 
established and judgment must be exercised in the placing of an 
arbitrary point in the transition zone to represent on the map the 
point of contact with reference to the physical features shown upon 
the base map. Proceeding with his work the field man will de- 
termine other points of contact, plotting the position with refer- 
ence to the physical features of the base map sketching the bound- 
ary of the soil type between the established points of contact. 
As he becomes more and more familiar with the character of the 
soil t\-pe, with the origin, derivation, and agencies of accumulation 
and with the physiographic position, he will be greatly assisted 
in the delineation of his soil boundaries by a knowledge of the 
geology of the region, by changes in color of the surface soil, by 
physiographic or topographic positions, such as the meandering of 
streams or the position and direction of slopes or hills, and not 
infrequently by a change in the character of native vegetation. 

The boundary- line between soil types will be indicated by a 
fine dotted black line placed upon the base map with a hard draw- 
ing pencil and the area inclosed within the lines representing a 
soil tj-pe ^vill be lightly colored by a crayon pencil and the number 
of the pencil will be placed on the base map in every area as well 
as upon a block in a legend attached to the map which is given the 
field name of the soil type. Great care must be used to number 
each area, however small, and to see that the same color is used 
for the same soil type wherever it occurs in the area. This is 
necessary in order to avoid confusion and mistakes in the assem- 
bling and redrawing c>f the base map in the office and to prevent 
error in the published map. WTiere phases of soil types have to 
be expressed the same color will be spread over the area as over 
the t\7)ical soil tj-pe, but rulings or conventional signs or sym- 
bols will be added without sharp boundary lines except where 
the phase comes in contact with different soil tj'pes. 

As the soil map is frequently to be used locally, it is important 
that the boundary lines be adjusted with respect to landhnes, 
roads, and houses, for the indi^•idual using the soil map in the 
field will locate himseh not with respect to primary control points 



MAPPING SOILS. 87 

but with respect to houses, roads, and streams. Care must be 
taken, especially where a soil boundary crosses a road near a clo- 
sure error shown on a plane table sheet, to indicate upon the map, 
for the information of the draftsman, the direction from which 
the boundary line of the soil type has been sketched and the 
direction in which any adjustment must be made in the soil 
boundary to correspond to any adjustment that will have to be 
made in the road circuit. 

In working away from a road where the odometer can not be used 
the location of the boundary line between soil types must usually 
be done by foot traverse or by intersection, and the boundary 
between points thus established must be sketched in at once in 
the field and never left until the day's work is finished. In 
other words, the delineation and mapping of the soil type must 
be done and completed in the field as the survey progresses, and 
no part of this must be done in the office or away from the point 
of observation. 

Proceeding in this way through the area, each soil type and 
phase is to be outlined on the base map. In case material is en- 
countered which differs so far from the typical conditions as to 
ra,ise a question as to whether it could be mapped as a phase or 
whether the differences are sufficient to justify a new type, the 
procedure should always be to map it as a separate type giving it 
a field name, as upon review by the field man, by the inspector, 
or by the correlation committee it is much easier to combine 
areas separately mapped than it is to separate types in areas which 
have been mapped as a single type and which subsequent investi- 
gation may show should have been separated. 

The smallest unit that can practically be shown upon a base 
map whose scale is 1 mile to an inch is 5 acres. It is impracti- 
cable to show on a base map of tliis scale very small areas without 
exaggeration. Such exaggeration is sometimes justifiable in the 
case of narrow meadow areas along stream courses, and occasionally 
where a very sharp contrast is shown in the texture or character 
of the soil material. On the other hand, there would be justifica- 
tion in the failure to map a phase or a soil condition somewhat 
greater in extent provided the difference is agriculturally unim- 



88 INSTIM'CTIOXS TO FIELD PARTIES. 

portant, or so apparent and so frequently repeated as to constitute 
a general feature that might be described in the report. 

It is important in order to economize time and conserve energy 
that the field man keep as close as possible to the actual field of 
work by frequently moving his headquarters, and in lading out 
the work ahead care should be taken to avoid driving over the 
same road oftener than is necessary. Careful attention to this 
matter of planning the work and equal' attention to accuracy of 
detail are necessary. The speed or rate of work is an important 
factor in measuring the efficiency of a field man. 

In the conduct of the soil survey the field men will see that 
I hey are supplied with published soil maps of any adjoining areas, 
and before they leave the field will prepare a note on the reasons, 
if any, why their work does not join up in detail with the work 
in adjoining areas already published. 

Where topographic sheets are used alone or in conjunction with 
the planetable traverse the field man must verify his traverse 
of drainage where there is an apparent disagreement as to the 
direction a soil area should be extended along stream courses. 

After a soil boundary has been fully established the dotted line 
previously drawn with a hard pencil is to be inked in indelible 
waterproof black ink, and before the sheet is finally sent to the 
office it should be carefully scrutinized to see that it is complete 
and legible in all details. In all cases a tracing or copy of the map 
must be made in the field, complete in every detail as to base map 
and soil map with legends, symbols, scale, and magnetic north 
and identification marks, and finally the field sheets, the office copy, 
the finished report, and all notes taken in the area should be sent 
under registered mail to the office, being careful to mail the field 
sheets and the office sheets at different times or places to insure 
delivery. The sheets upon which are the latest corrections should 
be indicated as the official copy of the soil map. 

Full notes should be taken as the work progresses as to the char- 
acter of the variations in the soil and as to the agriculture and other 
features that the field man will need in making up his final report. 

Full notes should be made in the field and drawings submitted 
suitable for the profile legend published on the soil maps. The 



ESTIMATING AND MAPPING ALKALI. 



89 



construction of these drawings is best learned through a study of 
the profiles that have been used on any of the recently published 
maps. The following is a complete list of the abbreviations used 
by the bureau in this profile work: 



Stone St. 

Gravel Gr. 

Sand S. 

Loam L. 

Silt Si. 

Clay C. 

Peat P. 

Slate Sla. 

Coarse Co. 

Fine F. 

Mica Mi. 

Very V. 

Meadow M. 

Black ., B . 

Gray G. 

Chalk Ch. 

Coastal beach Cb. 

Dunesand Ds. 

Gumbo Gu. 

Gypsum Gy. 

Alluvial sed iments Als. 



Madeland Ml. 

Marsh Ma. 

Rock R . 

Bed B. 

Muck Mu. 

Adobe A. 

Shale : Sh: 

Hardpan Hp. 

Light Li. 

Heavy H . 

Overwash O. 

Riverwash Rv. 

Rock outcrop Ro. 

Rough stony land Rsl. 

Rough broken land Rbl. 

Steep broken land Sbl. 

Sandhill S. H. 

Tidal marsh Tm. 

Igneous I. 

Limestone L. 



INSTRUCTIONS FOR ESTIMATING AND MAPPING 
ALKALI. 

Electrolytic Determination of Total Salts. 

Principles of electrolytic determination. — The alkali content, in 
terms of total salts, is determined in both soils and waters by the 
use of the electrolytic bridge.^ 

By this instrument the electrical resistance in ohms, at 60° F., 
to the passage of a current through a cell filled with the soil or 
water in which the salt concentration is to be estimated, is deter- 
mined. The resistance varies with the character and amount of 



1 For a more complete description of the principles and operation of the electro- 
lytic bridge, see Bulletins 8, 15, and 61, and Circular 6, Division of Soils, U. S. 
Department of Agriculture. 



90 INSTRUCTIONS TO FIELD PARTIES. 

the salts, decreasing as the concentration becomes greater. This 
rate of decrease in resistance with increase in concentrations of 
any one particular salt or mixture of salts may be graphically 
represented by a curve. Such a curve, constructed experimentally 
by observing the resistance corresponding to various concentrations 
of a salt solution, will constitute a scale or standardization curve, 
from which the approximate concentration of salt solutions of the 
same general character may be determined from the resistance 
readings. 

When for purposes of comparison and representation upon maps 
the alkali or salt content of soils is grouped into zones of various 
degrees of concentration, the electrical resistance corresponding to 
the concentration limits or lines of separation will constitute a 
series of limiting values when applied to the interpretation of 
readings in terms of total salt content. 

Instructions for operating the electrolytic bridge. — The irrigation 
water, or the soil, the electrical resistance of which is to be found, 
is put into the hard-rubber cell with metal electrodes. If the salt 
content of water is to be determined, the cell is filled even full 
with the water. If the salt content of soils is to be determined, 
the soil is placed in a cup and thoroughly mixed or worked with 
distilled water until a condition of saturation is reached, indicated 
by the appearance of free water. The cell is then filled with this 
material, gently tapping it on the ground to exclude air bubbles. 
The top of the soil is then struck off with a knife edge, so that the 
cell shall be just level full of the saturated soil. The cell is then 
suspended in the mercury cups or slipped into the spring contacts 
attached to the electrolytic bridge and the electrical resistance 
determined in the following way: 

The telephone receiver is pressed against the ear and the plunger 
of the instrument located at the center of the dial pressed down, 
when a buzzing sound will be heard in the receiver. Holding the _ 
plunger down so as to keep the battery switch closed, the pointerj 
is rotated to either right or left until the position is found at which^ 
the note in the telephone receiver is no longer heard or is only 
indistinctly heard. On rotating the pointer to either side of this 
position, the sound in the receiver should gradually increase. In 



ESTIMATING AND MAPPING ALKALI. 91 

case difficulty is found in locating the exact position of balance, it 
will be found of assistance to rotate the pointer rapidly back and 
forth over the position of least sound, locating points of equal 
intensity on either side. The mean position between these two 
points gives the position of balance, and the number opposite 
gives the desired reading. 

The sharpness of the minimum reading is much improved if the 
inner surfaces of the electrodes are kept clean and free from traces 
of grease. When waters are being tested, the cell should be occa- 
sionally cleaned with an alkaline solution or kept well scoured. 
The operator should avoid handling or touching the surfaces of the 
electrodes with the fingers. 

When a balance can not be obtained near the center of the 
bridge, the extra 100-ohm coil of the new-form bridge described in 
Bulletin 61 may be used in series with the cup by rotating to the 
"in" position. This 100 ohms must be deducted from the resist- 
ance reading to obtain the resistance of the cup contents. 

In case a balance is not obtained with the 1,000-ohm coil of the 
rotary switch, the 100-ohm and 10-ohm coils should be tried in 
succession. It is best to choose the coil which will bring the 
balance as near as possible to the center of the scale, as this is the 
most sensitive position. 

Having obtained the balance, the resistance is found by multi- 
plying the resistance of the comparison coil, as shown by the 
rotating switch, by the number on the scale opposite, the pointer. 
Thus, if the comparison coil used has a resistance of 100 ohms and 
the reading on the scale is 0.92, the resistance in the scale is 92 
ohms. If the comparison coil is 1,000 ohms and the reading on the 
scale is 4.5, the resistance would be 4,500 ohms. After taking the 
resistance in this manner, take the temperature immediately, 
either of the water or of the saturated soil, by sticking the bulb of 
a thermometer in and leaving it for some moments. The resistance 
is then corrected for this temperature according to the directions 
given below, ^ 

1 In order to dislodge raercury from the expansion chamber at the top of the 
stem in the field thermometer, shake the mercury into the expansion chamber 
as far as possible and heat the chamber in boiling water or over the flame of a match . 



92 



INSTRUCTIONS TO FIELD PARTIES. 



Reduction of resistances to a temperature of 60° F.—X single illus- 
tration will serve to show the way the following table is used in the 
reduction of electrical resistances to a uniform temperature of 60° F. 
Suppose the observed resistance of the soil is 2,585 ohms at a tem- 
perature of 50.5°. In the table, at the temperature of 50.5°, as 
indicated on the left-hand side, we find that at that temperature 
2,000 ohms is equal to 1,750 ohms at 60°; 5,000 ohms is equal to 
4,375 ohms at 60°; hence 500 ohms would be equal to 437 ohms. 
Similarly, 80 ohms would be one one-hundredth of the value given 
for 8,000 ohms at 50.5° in the table, therefore equal to about 70 ohms 
at 60°, while the 5 ohms would be equal to about 4 ohms. These 
separate values are added together thus: 



2,000 

500 

80 

5 



1,750 

437 

70 

4 



2, 585 ohms at 50.5^ 



261 ohms at 60°. 



Reduction of the electrical resistance of soils to a uniform temperature 
of 60° F. 



°F. 


1000 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


32.0 
32.5 


625 
632 


1,2.50 
1,264 


1,875 
1,896 


2,500 
2,528 


3, 125 
3,150 


3,750 
3,792 


4,375 
4,424 


5,000 
5,056 


5,625 
5,688 


33.0 
33.5 


6.39 
646 


1,278 
1,292 


1,917 
1,938 


2,556 

2,584 


3, 195 
3,230 


3,834 
3,876 


4,473 
4,522 


5,112 

5,168 


5,751 
5,814 


34.0 
34.5 


653 
660 


1,306 
1,320 


1,959 
1,980 


2,612 
2,640 


3,265 
3,300 


3,918 
3,960 


4,571 
4,620 


5,224 
5,280 


5,877 
5,940 


35.0 
35.5 


667 
674 


1,334 
1,348 


2,001 
2,022 


2,668 
2,696 


3,335 
3,370 


4,002 
4,044 


4,669 

4,718 


5,336 
5,392 


6,003 
6,066 


36.0 
36.5 


681 
688 


1,362 
1,376 


2,043 
2,064 


2,724 
2,752 


3, 405 
3,440 


4,086 
4,128 


4,767 
4,816 


5,448 
5,504 


6,129 
6,192 


37.0 
37.5 


695 
702 


1,390 
1,404 


2,085 
2,106 


2,780 
2,808 


3,475 ! 4,170 
3,510 ; 4,212 


4,865 
4,914 


5,560 
5,616 


6,255 
6,318 


38.0 
38.5 


709 
716 


1,418 
1,432 


2,127 
2,148 


2,8.36 
2,864 


3,545 4,254 
3,580 ' 4,296 


4,963 
5,012 


5,672 
5,728 


6,381 
6,444 


39.0 
39.5 


722 
729 


1,444 

1,458 


2,166 
2,187 


2,888 
2,916 


3,610 ' 4,332 
3,645 4,374 


5,054 
5,103 


5,776 
5,832 


6,498 
6,561 



ESTIMATING AND MAPPING ALKALI. 



93 



Reduction of the electrical resistance of soils to a uniform temperature 
of 60° i^.— Continued. 



°F. 


1000 


2000 


3000 


4000 


3000 


6000 


7000 


8000 


9000 


40.0 
40.5 


736 
743 


1,472 
1,486 


2,208 
2,229 


2,944 
2,972 


3,680 
3,715 


4,416 
4,458 


5,152 
5,201 


5,888 
5,944 


6,634 
6,687 


41.0 
41.5 


750 

757 


1,500 
1,514 


2,250 
2,271 


3,000 
3,028 


3, 750 

3,785 


4,500 
4,542 


5,250 
5,299 


6,000 
6,056 


6,750 
6,813 


42.0 
42.5 


763 
770 


1,526 
1,540 


2,289 
2,310 


3,052 
3,080 


3,815 
3,850 


4,578 
4,620 


5, 341 
5,390 


6,104 
6,160 


6,867 
6,930 


43.0 
43.5 


776 

782 


1,552 
1,564 


2,328 
2,346 


3,104 
3,128 


3,880 
3,910 


4,656 
4,692 


5,432 
5,474 


6,208 
6,256 


6,984 
7,038 


44.0 
44.5 


788 
794 


1,576 

1,588 


2,364 
2, 382 


3,152 
3,176 


3,940 
3,970 


4,728 
4,764 


5,516 
5,558 


6,304 
6,352 


7,092 
7,146 


45.0 
45.5 


800 

807 


1,600 
1,614 


2,400 
2,421 


3,200 
3,228 


4,000 
4,035 


4,800 
4,842 


5,600 
5,649 


6,400 
6,456 


7,200 
7,263 


46.0 
46.5 


814 
821 


1,628 
1,642 


2,442 
2,463 


3,256 
3,284 


4,070 
4,105 


4,884 
4,926 


5,698 

5,747 


6,512 
6,568 


7,326 

7,389 


47.0 
47.5 


828 
835 


1,656 
1,670 


2,484 
2,505 


3,312 
3,340 


4,140 
4,175 


4,968 
5,010 


5,796 
5,845 


6,624 
6,680 


7,452 
7,515 


48.0 
48.5 


842 
849 


1,684 
1,698 


2,526 
2,547 


3,368 
3,396 


4,210 
4,245 


5,052 
5,094 


5,884 
5,933 


6,736 
6,792 


7,578 
7,641 


49.0 
49.5 


856 
862 


1,712 
1,724 


2,568 
2,586 


3,424 

3,448 


4,280 
4,310 


5,136 
5,172 


5,992 
6,034 


6,848 
6,896 


7,704 

7,758 


50.0 
50.5 


868 

875 


1,736 
J, 750 


2,604 
2,625 


3,472 
3,500 


4,340 
4,375 


5,208 
5,250 


6,076 
6,125 


6,944 
7,000 


7,812 
7,875 


51.0 
51.5 


881 
887 


1,762 
1,774 


2,643 
2,661 


3,524 
3,548 


4,405 
^,435 


5,286 
5,322 


6,167 
6,209 


7,048 
7,096 


7,929 

7,983 


52.0 
52.5 


893 
900 


1,786 
1,800 


2,679 
2,700 


3,572 
3,600 


4,465 
4,500 


5,358 
5,400 


6,251 
6,300 


7,144 
7,200 


8,037 
8,100 


53.0 
53.5 


906 
912 


1,812 
1,824 


2,718 
2,736 


3,624 
3,648 


4,530 
4,560 


5,436 
5,472 


6,342 
6,384 


7,248 
7,296 


8,154 
8,208 


54.0 
54.5 


919 
926 


1,838 
1,852 


2,757 

2,778 


3,676 
3,704 


4,595 
4,630 


5,514 
5,556 


6,433 

6,482 


7,352 

7,408 


8,271 
8,334 


55.0 
55.5 


933 
940 


1,866 

1,880 


2,799 
2,820 


3,732 
3,760 


4,665 
4,700 


5,598 
5,640 


6,531 

6,580 


7,464 
7,526 


8,397 
8,460 


56.0 
56.5 


947 
954 


1,894 
1,908 


2,841 

2,862 


3,780 
3,816 


4,735 
4,770 


5,682 
5,724 


6,629 

6,678 


7,576 
7,632 


8,523 
8,586 


57.0 
57.5 


961 
968 


1,922 
1,936 


2,883 
2,904 


3,844 

3,872 


4,805 
4,839 


5,766 

5,807 


6,727 
6,775 


7,688 
7,743 


8,649 

8,711 


f8.0 

58.5 


974 
981 


1,948 
1,962 


2,922 
2,943 


3,896 
3,924 


4,870 
4,905 


5,844 
5,886 


6,818 
6,867 


7,792 

7,848 


8,766 
8,829 


59.0 
59.5 


987 
994 


1,974 

1,988 


2,962 

2,982 


3,949 
3,976 


4,936 
4,971 


5,923 
5,965 


6,910 
6,959 


7,898 
7,953 


8, 885 
8,947 



94 



INSTRUCTIOKS TO FIELD PARTIES. 



Reduction of the electrical resiHtance of soils to a uniform temperature 
of 60° F. — Coiitiuued. 



°F. 


1000 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


60.0 
60. 5 


1,000 
1,006 


2,000 
2, 012 


3,000 
3,018 


4,000 
4,024 


5,000 
5,030 


6,000 
6,036 


7, 000 
7,042 


8,000 
8,048 


9,000 
9,054 


61.0 
61.5 


1,013 
1,020 


2,026 
2, 040 


3,039 
3,060 


4,052 
4,080 


5,065 
5, 100 


6,078 
6,120 


7, 091 
7,140 


8, 104 
8,160 


9,117 
9, 180 


62.0 
62.5 


1,027 
1 , 033 


2,054 
2, 066 


3, 081 
3,099 


4,108 
4,132 


5,135 
5, 165 


6,162 
6, 198 


7,189 
7, 231 


8,216 
8,264 


9,243 
9,297 


63.0 
63.5 


1,040 
1 , 047 


2,080 
2, 094 


3,120 
3,141 


4, 160 
4,188 


5, 200 
5, 235 


6,240 
6,282 


7,280 
7, 329 


8,320 
8,376 


9,360 
9,423 


64.0 
64.5 


1,054 
1,061 


2, 108 
2,122 


3, 162 
3,183 


4,216 
4,244 


5,270 
5,305 


6,324 
6,366 


7,378 
7,427 


8,432 
8,488 


9, 486 
9,549 


65.0 
65.5 


1,068 
1,075 


2, 136 
2,150 


3,204 
3,225 


4,272 
4,300 


5,340 
5,375 


6,408 
6,450 


7,476 
7,525 


8,544 
8,600 


9,612 
9, 675 


6f). 
66.5 


1,082 
1,089 


2, 164 

2, 178 


3,246 
3,267 


4,328 1 5,410 
4,356 5,445 


6,492 
6,534 


7,574 
7,623 


8,656 
8,712 


9,738 
9,801 


67.0 
67.5 


1,096 
1,103 


2,192 
2,206 


3,288 
3,309 


4,384 
4,412 


5, 480 
5,515 


6,576 
6,618 


7,672 
7,721 


8,768 
8,824 


9,864 
9,927 


68.0 
68. 5 


1,110 
1,117 


2, 220 
2,234 


3,330 
3,3.ol 


4,440 
4,468 


5, 5.50 

5,585 


6,660 
6,702 


7,770 
7, 819 


8,880 9,990 
8,936 10,053 


69.0 
69.5 


1,125 
1,133 


2, 250 
2,266 


3,375 
3,399 


4,500 
4,532 


5,625 
5,665 


6, 750 
6,798 


7,875 
7,931 


9,000 
9,064 


10, 125 
10, 197 


70.0 1,140 
70.5 1,147 


2,280 
2, 294 


3,420 
3,441 


4,560 5,700 6,840 
4,588 5,735 6,882 


7,980 
8,029 


9,120 
9,176 


10, 260 
10,323 


71.0 1,155 
71.5 1,162 


2,310 
2, 324 


3,465 
3,486 


4,620 i 5,775 1 6,930 
4,648 5,810 6,972 


8,085 
8,134 


9,240 
9,296 


10,395 
10,458 


72.0 1.170 
72.5 1,177 


2,340 
2,354 


3,510 
3,531 


4,680 
4,708 


5,850 7,028 
5,885 7,062 


8, 190 
8,239 


9, 360 
9,416 


10, 530 
10,593 


73.0 1,185 
73.5 ' 1,193 


2, 370 
2,386 


3, 5.55 
3,579 


4,740 
4,772 


5,925 
5,965 


7,110 

7, 158 


8,295 
8, 351 


9,480 
9,544 


10, 665 
10, 737 


74.0 1,201 
74.5 1,208 


2,402 
2,416 


3,603 
3,624 


4,804 
4,832 


6,005 
6,040 


7, 206 
7,248 


8,407 
8,456 


9,608 
9,664 


10,809 
10, 872 


75.0 1,215 
75.5 1,222 


2, 430 
2,444 


3,645 
3, 666 


4,860 

4,888 


6,075 
6,110 


7, 290 
7,332 


8,505 
8,554 


9,720 


10, 935 
10,998 


76.0 1,230 
76.5 1 1,238 


2,460 
2,476 


3,690 
3,714 


4,920 
4,952 


6, 158 
6,190 


7, 380 
7,428 


8,610 
8,666 


9,840 
9,904 


11,070 
11,142 


77.0 1,246 
77.5 1,254 


2,492 
2,508 


3,738 
3,762 


4,984 
5,016 


6,230 
6,270 


7,476 
7,524 


8,722 
8,778 


9,968 
10,032 


11,214 
11,286 


78.0 1,2()2 
78.5 1,270 


2, 524 
2, 540 


3,786 
3,810 


5,048 
5,080 


6,310 
6,350 


7,572 
7,620 


8,834 
8,890 


10, 096 
10, 160 


11,358 
11,430 


79.0 


1,278 
1,286 


2, 556 
2,572 


3,834 
3,858 


5,112 
5,144 


6,390 ' 7,668 
6,430 7,716 


8,946 
9,002 


10, 224 
10, 288 


11,502 
11,574 



ESTIMATING AND MAPPING ALKALI. 



95 



Reduction of the electrical resistance of soils to a uniform temperature 
of 60° F.—Gont'mued. 



°F. 


1000 


2000 


3000 


4000 


5000 


6000 


7000 


8000 


9000 


80.0 
80.5 


1,294 
1,302 


2,588 
2,604 


3,882 
3,906' 


5,176 
5,208 


6,470 
6,510 


7,754 
7,812 


9,058 
9,114 


10,352 
10, 416 


11,646 
11,718 


81.0 
81.5 


1,310 
1,318 


2,620 
2,636 


3,930 
3,954 


5,240 
5,272 


6,550 
6,590 


7,860 
7,908 


9,170 
9,226 


10, 480 
10, 544 


11,790 
11,862 


82.0 
82.5 


1,327 
1,335 


2,654 
2,670 


3,981 
4,005 


5,308 
5,340 


6,635 
6,675 


7,962 
8,010 


9,289 
9,345 


10, 616 
10, 680 


11,943 
12,015 


83.0 
83.5 


1,343 
1,351 


2,686 
2,702 


4,029 
4,053 


5,372 
5,404 


6,715 
6,755 


8,058 
8,106 


9,401 
9,457 


10, 744 
10,808 


12,087 
12,159 


84.0 
84.5 


1,359 
1,367 


2,718 
2,734 


4,077 
4,101 


5,436 
5,468 


6,795 
6,835 


8,154 
8,202 


9,513 
9,569 


10,872 
10,936 


12,231 
12,303 


85.0 
85.5 


1,376 
1,385 


2,752 
2,770 


4,128 
4,155 


5,504 
5,540 


6,880 
6,925 


8,256 
8,310 


9,632 
9,695 


11,008 
11, 080 


12,384 
12, 465 


86.0 
86.5 


1,393 
1,401 


2,786 
2,802 


4,179 
4,203 


5,572 
5,604 


6,965 
7,005 


8,358 
8,406 


9,751 
9,807 


11,144 
11,208 


12,537 
12,609 


87.0 
87.5 


1,409 
1,418 


2,818 
2,836 


4,227 
4,254 


5,636 
5,672 


7,045 
7,090 


8,454 
8,508 


9,863 
9,931 


11, 272 
11,344 


12,681 
12, 762 


88.0 

88.5 


1,427 
1,435 


2,854 
2,870" 


4,281 
4,305 


5,708 
5,740 


7,135 
7,175 


8,562 
8,610 


9,989 
10,040 


11,416 
11,480 


12,843 
12,915 


89.0 
89.5 


1,443 
1,451 


2,886 
2,902 


4,329 
4,353 


5,772 
5,804 


7,215 
7,255 


8,658 
8,706 


10,091 
10, 157 


11,544 
11,608 


12,987 
13,059 


90.0 
90.5 


1,460 
1,468 


2,920 
2,936 


4,380 
4,404 


5,840 
5,872 


7,300 
7,340 


8,760 
8,808 


10,220 
10, 276 


11, 680 
11,744 


13,140 
13,212 


91.0 
91.5 


1,477 
1,486 


2,954 
2,972 


4,431 

4,458 


5,908 
5,944 


7,385 
7,430 


8,862 
8,916 


10,339 
10, 402 


11,816 
11,888 


13, 293 
13, 374 


92.0 
92.5 


1,495 
1,504 


2,990 
3,008 


4,485 
4,512 


5,980 
6,016 


7,475 
7,520 


8,970 
9,024 


10,465 
10,528 


11,960 
12,032 


13, 455 
13,536 


93.0 
93.5 


1,513 
1,522 


3,026 
3,044 


4,539 
4,566 


6,052 
6,088 


7,565 
7,610 


9,078 
9,132 


10,591 
10,654 


12, 104 
12,176 


13, 617 
13,698 


94.0 
94.5 


1,531 
1,540 


3,062 
3,080 


4,593 
4,620 


6,124 
6,160 


7,655 
7,700 


9,186 
9,240 


10, 717 
10, 780 


12,248 
12,320 


13, 779 
13,860 


95.0 
95.5 


1,549 
1,559 


3,098 
3,118 


4,647 
4,677 


6,196 
6,236 


7,745 
7,795 


9,294 
9,354 


10,843 
10,913 


12,392 
12, 472 


13,941 
14,031 


96.0 
96.5 


1,569 
1,579 


3,138 
3,158 


4,707 
4,737 


6,276 
6,316 


7,845 
7,895 


9,414 
9,474 


10,983 
11,053 


12,552 
12,632 


14, 121 
14,211 


97.0 

97.5 


1,589 
1,599 


3, 178 
3,198 


4,767 
4,797 


6,356 
6,396 


7,945 
7,995 


9,534 
9,594 


11, 123 
11, 193 


12,712 
12,792 


14,301 
14,391 


98.0 
98.5 


1,609 
1,619 


3,218 
3,238 


4,827 
4,857 


6,436 
6,476 


8,045 
8,095 


9,654 
9,714 


11,263 
11,333 


12,872 
12,952 


14, 481 
14,571 


99.0 


1,629 


3,258 


4,887 


6,516 


8,145 


9,774 


11,403 


13,032 


14,661 



42126—1^ 



96 



INSTRUCTIONS TO FIELD PARTIES. 



Concentration intervals. — The concentration limits adopted 
in the classification of alkali salts in the usual alkali surveys are, 
respectively, 200, 400, 600, 1,000, and 3,000 parts per 100,000 of 
total salts in the dry soil, the maps showing extent and distri- 
bution of the several grades of concentration being constructed 
in the field directly from field readings. 

Interpretation of bridge readings. — From the results of experi- 
mental data obtained in the bureau laboratories, the following 
tables have been constructed from plotted curves. From these 
may be interpreted the values of the corrected electrical resistances 
in terms of the various concentrations of salts. 

These values are found of sufficient accuracy to warrant their 
use in all reconnoissance work, and can be used in alkali surveys 
involving approximate determinations over limited areas, or in 
all alkali surveys where subject to check by independent standardi- 
zation. In case unusual accuracy is required or it is found that the 
tables do not give reliable results, a new curve will be furnished by 
the bureau laboratories, or this may, if necessary, be constructed 
in the field according to directions which follow on page 99. 

In areas in which the salts present consist predominantly of 
sulphates and chlorides with little or no carbonates or black alkali 
present the values are determined from the following table: 

Concentration values of resistances in soils containing sulphates and 
chlorides. 



Salt 

content 

(sul- 


1 
Resistance at 60° F. 1 

, 1 


phates 
and chlo- 
rides). 


Sand. 


Loam, j a. Clay. 

1 ! 


Aver- 
age. 


Parts ver 

100,000. 

3,000 

1,000 

600 

400 

200 


Ohms. 
17.8 
36.4 
55.4 
83.6 
153.0 


Ohms. 
17.9 
37.9 
57.6 
68.8 
158.9 


Ohms. 
19.0 
41.5 
62.0 
92.5 
164.5 


Ohms. 
21.0 
44.5 

68.4 
98.5 
174.1 


Ohms. 
18.9 
40.1 
60.9 
90.4 

162.6 



ESTIMATING AND MAPPING ALKALI. 



97 



For general field work the averages of the following table may be 
used when carbonates are absent, as the values for the different 
classes of soil differ but slightly. 

For convenience, where it is desired to determine more closely 
the quantities of alkali lying between those expressed in the con- 
centration limits, the following table may be used. Where car- 
bonates constitute a considerable proportion of the total salts 
present the tables on page 98 should be used in the interpretation 
of results. 



Amounts of salts in soils containing predominantly sulphates and 
chlorides with given resistances. 



1 Resist- 
ance at 
60° F. 


Sand. 


Loam. 


Clay 
loam. 


Clay. 


Resist- 
ance at 
60° F. 


Sand. 


Loam. 


Clay 
loam. 


Clay. 




Parts 


Parts 


Parts 


Parts 




Parts 


Parts 


Parts 


Parts 


Ohms. 
18 


per 
100,000 
3.000 


100,000 
3,000 


100,000 


m%oo 


Ohms. 
95 


mjooo 

350 


100,000 
370 


100^000 


100,000 
420 


19 


2,400 


2,640 


"s'ooo" 




100 


330 


350 


370 


390 


20 


2,200 


2,420 


2,800 


'3,'66o' 


105 


310 


330 


350 


370 


25 


1,500 


1,700 


1,940 


2,200 


110 


300 


320 


330 


350 


30 


1,240 


1,340 


1,460 


1,580 


115 


280 


290 


310 


330 


35 


1,040 


1,140 


1,220 


1,320 


120 


270 


280 


290 


320 


40 


860 


940 


1,040 


1,140 


125 


250 


2m 


280 


300 


45 


750 


780 


880 


980 


130 


240 


250 


260 


280 


50 


670 


710 


770 


860 


135 


230 


240 


250 


270 


55 


600 


640 


690 


770 


140 


220 


230 


240 


260 


60 


550 


580 


630 


700 


145 


210 


220 


230 


250 


65 


510 


540 


570 


630 


150 


210 


210 


220 


240 


70 


480 


500 


530 


590 


155 


200 


210 


210 


230 


75 


450 


470 


500 


550 


160 


200 


200 


210 


220 


80 


420 


440 


470 


510 


165 


190 


-200 


200 


210 


85 


390 


420 


440 480 


170 


190 


a90 


200 


200 


90 


370 390 


410 450 













98 INSTRUCTIONS TO FIELD PARTIES. 

Concentration values of resistances in soils containing carbonates. 



Salt con- 
tent. 


Resistaiice at 60° F. 


Sand. 


Loam. 


Clay 
loam. 


Clay. 


Parts per 

100,000. 

3,000 

1,000 

600 

400 

200 


Ohms. 
23.6 
54.7 
82.6 
131.6 
270.6 


Ohms. 

24.6 

68.5 

114.8 

168.1 

312.3 


Ohms. 

24.6 

69.4 

126.2 

201.9 

376.2 


Ohms. 
30.0 
96.1 
152.5 
216.2 
377.4 



Amount of salts in soil types containing carbonates ivith given resisi 



Resist- 
ance at 
60° F. 


Sand. 


Loam. 


Clay 
loam. 


Clay. 


Resist- 
ance at 
60° 1. 


Sand. 


Loam. 


Clay 
loam. 


Clay. 




Parts 


Parts 


Parts 


Parts 




Parts 


Parts 


Parts 


Parts 




per 


per 


per 


per 




per 


per 


per 


per 


Ohms. 


100,000 


100,000 


100,000 


100,000 


Ohms. 


100,000 


100,000 


100,000 


100,000 


24 

25 


3,000 
2,900 








130 
135 


410 
390 


530 
510 


590 
570 


720 
690 


3,666 


3,000 




30 


2,100 


2,220 


2,220 


3,000 


140 


380 


490 


550 


660 1 


35 


1,640 


1,910 


1,910 


2,550 


145 


370 


470 


530 


630 


40 


1,420 


1,720 


1,740 


2,280 


150 


360 


450 


510 


610 


45 


1,240 


1,540 


1.560 


2,050 


155 


350 


440 


500 


590 


50 


1,300 


1,400 


1:420 


1,870 


160 


340 


430 


490 


560 


55 


1,000 


1,270 


1,290 


1,720 


165 


330 


410 


470 


540 


60 


870 


1,160 


1,180 


1,600 


170 


320 


400 


460 


520 


65 


800 


1 060 


1,080 


1,480 


175 


310 


390 


450 


510 


70 


740 


980 


1,000 


1,380 


180 


310 


380 


440 


490 


75 


680 


920 


950 


1,290 


185 


300 


370 


430 


470 


80 


640 


860 


900 


1,220 


190 


300 


360 


420 


460 


85 


590 


810 


860 


1,140 


195 


290 


350 


410 


450 


90 


560 


770 


820 


1,080 


200 


290 


340 


400 


430 


95 


540 


730 


790 


1,010 


210 


260 


320 


380 


390 


100 


510 


690 


750 


970 


220 


240 


310 


370 


360 


105 


490 


650 


720 


910 


240 


210 


280 


340 


330 


110 


470 


630 


690 


870 


260 


190 


260 


320 


310 


115 


450 


600 


660 


830 


300 




220 


280 


290 


120 


430 


570 


640 


790 


340 




180 


230 


240 


125 


420 


550 


610 


750 


380 






200 


200 







Directions for making standardizations.- — If greater accuracy be 
desired or if it be believed that the values given in the tables are 



I 



ESTIMATING AND MAPPING ALKALI. 99 

not applicable to the conditions, a standardization curve and tables 
may be constructed for each district or area by the following 
methods, reducing all resistances to the basis of 60° F. by use of the 
preceding tables. 

For this purpose 8 or 10 crusts including the top inch of soil and 
so selected as to represent the average crusts of the entire area to be 
surveyed should be collected. If crusts can not be obtained use 
the strongest alkali soils collected from different places from the 
whole area. It is recommended that this material be immediately 
forwarded to the bureau with request for a standardization curve, 
but in cases of necessity this can be determined in the field by the 
following methods: 

The crusts or soil samples should be thoroughly mixed together. 
Of this mixture take several hundred grams and add about twice 
its volume of distilled water. Stir thoroughly and filter off the • 
solution. Evaporate 100 c. c. of this solution in a weighed vessel 
to dryness. Gently ignite to remove water of crystallization and 
organic matter. Allow the vessel to cool, and re weigh. ^ The 
gain in weight of the vessel in grams is equal to the percentage of 
salt in the solution. Preserve the residue in the dish to test for 
carbonates, or test the original sDlution. If the solution is stronger 
than 3 per cent, it should be diluted until it is of that strength; if it 
is weaker, it should be concentrated by evaporation until it is 
approximately 3 per cent. If necessary to concentrate, then deter- 
mine after concentration exactly how much salt is in 100 c. c. by 
evaporation in a weighed vessel, as before, and make the neces- 
sary dilution of the main solution in order to obtain a 3 per cent 
salt content. Having obtained a 3 per cent solution, measure its 
resistance. Then by systematic dilution make 1.00, 0.60, 0.40, 
and 0.20 per cent solutions, and measure the resistance of each, re- 
ducing the values to 60° F. The dilutions may be made as follows: 
33.3 c. c. of 3 per cent diluted to 100 c. c. gives 1 per cent solution; 
60 c. c. of 1 per cent solution diluted to 100 c. c. gives 0.60 per cent 
solution; 66.7 c. c. of 0.60 per cent solution diluted to 100 c. c. gives 
0.40 per cent solution; and 50 c. c. of 0.40 per cent solution diluted 

1 Ifcare is used, weighing may be done upon druggists' scales, 15.5 grains equaling 
1 gram. 



100 



INSTRUCTIONS TO FIELD PARTIES. 



to 100 c. c. gives 0.20 per cent solution. Now test the residue from 
evaporation for carbonates by the addition of hydrochloric acid. 
(\xrbonates will cause an effervescence. If there is little or no 
carbonate present, the resistances of the solution at the various per- 
centages multiplied by the ratios in the following table for the 
\arious classes of soils give the resistances of the saturated soil with 
the same percentage salt content in tlie dry soil. 

Batlo of soil, resistance to solution resistance. 



Sand. 


Loam. 


Clay 1 p, ^. 
loam. ^^^^ ■ 


1.48 
1.46 
1.42 
1.44 
1.44 


1.49 
l.')3 
1.48 
1.49 
1.50 


1.58 ' 1.75 
1.66 j 1.76 

1.59 1.76 

1.60 1.70 
1.57 1.64 


1.45 


1.50 


1.60 1.72 



These resistances or limiting values are to be inserted in the 
])roper place in the following tables, conversion of the salt content 
as expressed in terms of per cent to parts per 100.000 l)eing made by 
simple calculation. 

Table of limiting values. 



Salt ip 
soil. 


Sand and 
sandy 
loam. 


Loam. 


Clay 
loam. 


Clay. 


Parts per 

100,000. 

3,000 

1,000 

600 

400 

200 


Ohms. 


Ohms. 


Ohms. 


Ohms. 








::::::::::i 








i. 








1 








. 1 








1 



If the test for carbonates shows that there is much of those salts 
]) resent, the measured resistances for the solution should be multi- 
])lied by the ratios given in Table X, for the given concentrations, 



ALKALI MAPS. 



101 



assuming one-third the salt present to be carbonate. For excep- 
tional accuracy, the percentages of carbonates in the salt may be 
determined and a corresponding new ratio, proportional to the 
amount of carbonate present, obtained. 

Table X. — Ratios of resistances of soils containing carbonates to 
resistances of solution containing carbonates. 



Parts per 
100,000. 


Sand. 


Loam. 


Clay 
loam. 


Clay. 


3,000 

1,000 

600 

400 

200 


1.53 
1.70 
1.75 
1.83 
1.89 


1.69 
1.95 
2.09 
2.10 
2.11 


1.76 
2.02 
2.26 
2.40 
2.40 


1.98 

2.48 
2.70 
2.56 
2.48 



Note.— If it is desirable to determine the 3 per cent limit in the soil, portions 
of the composite solution will have to be concentrated by evaporation according to 
the above directions so as to contain the percentage of salt given in the table. The 
cell filled with such concentrated solutions gives a resistance too low to be read on 
the instrument, and it will be necessary to take a measured amoimt of the solution 
in the cell, as for example, one-fourth or one-fifth its capacity. Determine the 
resistance and divide it by 4 or 5, as the case may be. This gives the resistance of 
the cell when filled. For these concentrated solutions the readings will be rather 
indefinite. Keep the cell electrodes well cleaned at all times. 

Alkali Maps. 

Principles of alkali mapping. — In representing alkali areas upon 
the map the soils are grouped between certain arbitrary limits based 
upon the average amount of the alkali present in the soil to a depth 
of 6 feet. The alkali content is stated in terms of parts of total salts 
per 100,000 of the dry soil. In cases in which much greater concen- 
trations of the total salts than would be indicated by. the average 
amount occur locally in the surface foot or in some other section of 
the profile, such concentrations may be indicated upon the map by 
rulings or symbols as explained later. 

In the construction of the usual total alkali maps the first grade, 
or lowest degree of concentration represented , includ es areas in which 
the amount of total alkali salts is less than 200 parts per 100,000 of 



102 INSTRUCTIONS TO FIELD PARTIES. 

the dry soil. This gi-ade represents conditions under which all 
ordinary crops may be grown with but little or no apparent injury. 

The second grade of soil includes areas containing from 200 to 
400 parts of soluble salts per 100,000 of the dry soil. Soils cf this 
grade fall within the first limits of danger, for while under favorable 
conditions the more hardy crops may escape injury, ban-en spots, 
or other evidences of injury to the less tolerant plants such as most 
grains, young or sensitive vegetables, beans, citrus, and many other 
fruits, are frequently observed. "When accompanied by more 
highly concentrated accumulations at the sm'face, alkali crusts and 
barren spots may occur in fields of alfalfa or other of the more resist- 
ant crops. 

The thhd grade covers areas in which the total salt content ranges 
from 400 to 600 parts per 100,000. Such concentrations are usually 
marked by the occurrence of frequent barren spots, by the formation 
of alkali crusts, the growth of characteristic alkali vegetation, and 
by a consequent marked decrease in yields or complete faiiiu-e of 
crops. 

In the succeeding two grades the quantity of total salts ranges 
from 600 to 1,000 parts per 100,000, and from 1,000 to 3,000 parts per 
100,000, respectively. On land of this character there is generally 
a failure of all but the most tolerant crops. 

The last grade of concentration in the classification embraces soils 
containing more than 3,000 parts of total salts per 100,000 of dry 
soil — a condition seldom encountered except in the barren beds of 
desiccated salt lakes. 

Owing to the usual occurrence of a mixture of salts in varying 
proportions in alkali soils, the degree of injury resulting from equal 
concentrations varies. Only in the case of the occurrence of an ex- 
cess of the sodium carbonate, or black alkali, however, is the differ- 
ence so great as to require a separate basis of classification. In such 
case an additional black alkali map is constructed, upon which is 
indicated the amount of sodium carbonate occurring in the surface 
foot. 

The lowest grade of concentration represented is less than CO 
parts per 100,000 of dry soil, and like the lowest grade of the total 
salts is generally negligible as far as injury to crops is concerned. 



ALKALI MAPS. 103 

The second grade embraces soils carrying from 50 to 100 parts of 
sodium carbonate per 100,000 of the dry soil. As with the second 
grade recognized in case of the total salts, occasional barren spots 
and unproductive areas may in such cases appear. 

The third grade includes soil areas in which from 100 to 200 parts 
sodium carbonate to 100,000 of dry soil occur. In such areas will 
occur many unproductive areas occupied by the more resistant 
weeds and shrubs, or existing as barren spots, easily recognized by 
their black color and encrusted surface. 

The two higher grades of concentration recognized in the classifi- 
cation of black alkali lands embrace soils containing from 200 to 300 
parts, and more than 300 parts sodium carbonate per 100,000 of dry 
soil, respectively. The conditions in such soils are prohibitive of 
crop production under all ordinary circumstances. 

Construction of total alkali maps. — Sampling for alkali determina- 
tions is done with the ordinary 6-foot soil auger, the sample being 
separated into foot sections and placed upon small sheets of oilcloth 
or similar material of convenient size. Gravel and roots or other 
extraneous matter are removed and the sample prepared for elec- 
trolytic determination as previously described. The location of 
all borings made for alkali determinations, with brief descriptions 
of the texture and structure of the soil, topography, drainage fea- 
tures, character of native vegetation, condition of crops, original 
resistance, cell temperature, corrected resistance, and salt content 
should be entered in the Alkali Fiefd Book and the number and 
location of the boring indicated upon the field alkali map. The 
amount of alkali salts in each sectional foot of soil to a depth of 6 
feet is to be determined in accordance with the directions pre- 
\iously given in this publication . In many cases after the observer 
becomes familiar with the soils and alkali conditions of a locality 
the field work may be materially shortened by making the alkali 
determinations in alternate foot sections or by mixing two or more 
foot sections for a single composite salt determination. 

The average amount of total alkali salts is determined by com- 
puting the average of the salt contents of each of the six 1-foot 
sections. For representing this average amount a color is selected 
and applied to the map in the appropriate location, which may be 



ALKALI MAPS. 105 

representing one-fourth of the total vohime of saturated soil, with 
N/20 acid potassium sulphate containing 6.811 grams per liter, using 
phenolphthalein as an indicator. This will represent the carbo- 
nates. Then add a drop or so of methyl orange or congo red and 
again titrate with N/20 acid potassium sulphate. Subtract an 
amount equal to the first titration from the second, and the differ- 
ence represents the bicarbonates. Add a few drops of potassium 
chromate as an indicator to the same solution and titrate with N/10 
silver nitrate . This will represent the chlorides. The salts are all 
to be estimated as sodium salts, as follows: 

1 c. c. N/20 HKSO4 is equivalent to 0.005305 gram NajCOg. 

1 c. c. N/20 HKSO4 is equivalent to 0.004203 gram NaHCOg. 

1 c. c. N/10 AgNOa is equivalent to 0.00585 gram NaCl. 
Construction of black alkali maps. — In areas where the construc- 
tion of a black alkali map is warranted, the classification of the soils 
into the various grades of concentration is effected in the field from 
the volume of N/20 acid potassium sulphate used in titration for 
carbonates in the surface foot, the various grades being represented 
by selected colors as in case of the total alkali map. The limiting 
values corresponding to the concentration grades of less than 50 
parts, 50 to 100 parts, 100 to 200 parts, 200 to 300 parts, and more 
than 300 parts sodium carbonate per 100,000 of dry soil, in terms of 
the number of cubic centimeters N/20 acid potassium sulphate used 
in titration, are determined as follows : 

Each of the brass cones accompanying the alkali field outfit is 
stamped with its volume capacity in cubic centimeters. When 
this amount is diluted to 200 c. c. in the flask or bottle and 50 c. c. 
of this volume of solution taken for titration, the volume of soil 
represented by the solution used in titration will amount to one- 
fourth the volume of the cone. Should the volume of the bottle 
or flask used in making up the soil solution be greater or less than 
200 c. c, the volume of soil represented by the amount taken for 
titration will be greater or less than one-fourth the contents of the 
cone, and should be computed. 

This volume of saturated soil represented by the amount of solu- 
tion taken for titration should now be multiplied for the various 



i 



106 



INSTRUCTIONS TO FIELD PARTIES. 



concentration intervals and for the various classes of soils by the 
factors in the follovrinfi: table: 



TCti^o, Sand and 


Loam. 


Clay 
loam. 


Clay. 


Parts per 

100,000. 

300 

200 

100 

50 


0.832 
,554 
.277 
.138 


0.752 
.502 
.251 
.125 


0.720 
.480 
.240 
.120 


0.689 
.459 
.230 
.115 1 



The results thus obtained are the number of cubic centimeters of 
X/20 acid potassium sulphate solution used in titrating the carbo- 
nates, corresponding to the concentration limits and are to be 
inserted in the following table: 



NasCOs 
in soil. 


Sand andi j p, 
sandy Loam. ffi. 


Clay. 


Parts per 

100,000. 

300 

200 

100 

50 


c.c. 


c. c. 


c. c. 


c. c. 


; 1 ■■". 


1 ' 1 







If it is desired to reduce the volume of X/10 AgXOg to percent 
or amount in terms of parts per 100,000 of XaCl in dry soil, the 
following formula may be used: 

V 0.00585 

Substituting 0.004203 for 0.00585, the same formula may be used to 
reduce the volume of X/20 HKSO4 to per cent of XaHCOg. V= 
cubic centimeters X/10 AgXOg or X'^/20 HKSO4 solution used; 
V^= volume saturated soil represented in amount of solution 
titrated; K=constant for t}^e of soil as follows: Sand and sandy 
loam=1.46; loam=1.32; clay loam=1.26; clay=1.21. 



IKSTRUCTIONS TO FIELD PARTIES. 



107 



Determination op Total Salts in Water. 

The total salt content of irrigating, drainage, or other waters, in 
parts per 100,000, may be determined within a reasonable degree of 
accuracy from the following table, the resistance at 60° F. being 
ascertained according to the directions given in the preceding 
pages. The curve varies according to the character of the salts 
present.' Where no carbonates are present in the water, the 
figures in the column marked "Chlorides" should be used. When 
preliminary examination by titration indicates that more than 50 
per cent of the total salts is carbonates, the figures in the column 
marked "Carbonates" should be used. For intermediate per- 
centages of carbonates, a corresponding intermediate value be- 
tween those given in the two columns should be used. 

For using the bridge with water or soil solutions, the cup is 
filled with the solution and the reading of resistance made just as 
with soils. After correcting for temperature, the parts per 100,000 
of salt in solution are determined by use of the following table: 

Table for determining total salt content of water from resistance at 60° F. 



Resist- 
ance 
60° F. 


Chlo- 
rides. 


Car- 
bon- 
ates. 


Resist- 
ance 
60° F. 


Chlo- 
rides. 


Car- 
bon- 
ates. 


Resist- 
ance 
60° F. 


Chlo- 
rides. 


Car- 
bon- 
ates. 




Pts. per 100,000. 




Pts. per 


100,000. 




Pis. per 


100,000. 


30 


750 


140 


141 


200 


340 


50 


71 


35 


670 


150 


132 


187 


360 


47 


65 


40 


595 


160 


124 


176 


380 


44 


60 


45 


525 


170 


116 


165 


400 


41 


55 


50 


460 


460 


180 


109 


154 


450 


35 


46 


55 


400 


425 


190 


102 


144 


500 


31 


38 


60 


355 


395 


200 


96 


138 


550 


28 


32 


65 


305 


375 


210 


91 


130 


600 


25 


27 


70 


265 


355 


220 


87 


122 


700 


22 


23 


75 


230 


335 


230 


83 


116 


800 







80 


213 


320 


240 


79 


110 


900 




9 


85 


203 


306 


250 


75 


105 


1,000 




8 


90 


195 


294 


260 


71 


100 


1,200 




L7 


95 


188 


284 


270 


68 


95 


1,400 




6 


100 


181 


262 


280 


65 


90 


1,600 




6 


110 


170 


250 


290 


62 


86 


1,800 




5 


120 


160 


231 


300 


59 


83 


2,000 




5 


130 


150 


213 


320 


54 


77 









108 INSTRUCTIONS TO FIELD PARTIES. 

The electrolytic cells are made as nearly of the same dimensions 
as possible, but if there is much variation in either volume or shape 
this table must not be used without a correction for the cell. 

If greater accuracy is desired than can be expected by the use of 
the above table, proceed in the following way: 

Collect 6 or 8 samples of water from different parts of the area, ' 
determine the electrical resistance of each, and take an amount of 
each proportional to the resistance, mixing them in a clean vessel. , . 
There should be at least 2 quarts, and preferably 1 gallon, of thief I 
mixture. Evaporate slowly on a stove until the mixture is about 
as strong as the strongest water likely to be encountered. If there 
is any possibility of encountering water as strong as a 1 per cent 
solution— that is, 1,000 parts of salts in 100,000 parts of water — 
the mixture should be evaporated until it gives a resistance in the 
cell of about 23 ohms. The amount of this evaporation can be 
determined by the original resistance of the mixture. If the 
resistance of the mixture is 100 ohms, it should be evaporated to 
one-fourth its volume to make approximately a 1 per cent solution. 
If the resistance is 400 ohms, the solution should be evaporated to 
one twenty-third of its original volume. Water having a resistance 
of 400 ohms would have a salt content, according to the above 
table, of about 44 in 100,000, and would be considered an excellent 
water for irrigation purposes. It would require 3 gallons of such 
water evaporated to 1 pint to make a 1 per cent solution. 

Determine the percentage of salts in this solution by evaporation 
to dryness. If necessary, the weights may be determined by 
weighing on druggist's scales. 

Take the concentrated solution and dilute with successive quan- 
tities of distilled water, so as to change the concentration of the 
solution and get the corresponding resistances in the cell. Use, 
for example, 9 parts of the solution and 1 part distilled water, then 
8 parts of the solution and 2 parts of distilled water, and so on 
down to any dilation likely to be encountered. This will give the 
resistance corresponding very exactly with known amounts of salt, 
and will furnish a table for the estimation of the salt content from 
the resistance of any water in the area. 

The table constructed from these data can be used directly by 
interpolation, or preferably a curve should be constructed and any 
intermediate points picked out from this. 



INSTRUCTIONS TO FIELD PARTIES. 109 

Care of Electrolytic Bridge. 

The bridge is a delicate instrument, and care should be exercised 
that it is not damaged by persons unfamiliar with its construction 
and use. It should not be subjected to any knocks and jars that can 
be avoided. By rough handling the connections are liable to be 
broken, the balancing mechanism injured, or parts jostled out of 
place. The accumulation of dust on its parts may be injurious, 
hence the box should not be left open when not in use. The bridge 
wire should be occasionally wiped off with a soft cloth to remove 
dust that may have collected on it. All the contacts should be 
occasionally cleaned. Dust on the interrupter of the induction 
coil may cause trouble. It may be cleaned with a fine brush or soft 
cloth. Should any of the soldered connections of the bridge be 
broken, the bridge should be sent to an electrician for repair. 

Testing the bridge. — The introduction of the 100-ohm coil (cup 
coil) in the arm of the bridge with the cup is useful not only in 
making measurements on concentrated solutions but also to test 
the correctness of the bridge. In place of the cup a heavy metal 
piece supplied for the purpose connects the cup clips. On throw- 
ing in the extra 100-ohm coil it is the only resistance in that arm of 
the bridge and should be balanced by 100 ohms in the known arm. 
If the bridge is in working order, but if the 100 ohms in the cup 
arm are not balanced by 100 ohms in the comparison coil arm, then 
correction must be made for the difference. Should the difference 
be very great, the bridge is probably out of order and should be 
repaired by a competent electrician. 

Location of faults. — The bridge is so designed that it may have 
the least possible likelihood of damage, but occasionally it may fail 
to work. Some probable causes for this are as follows: 

On pressing down the plunger no sound may be heard in the tele- 
phone receiver for any of the following reasons: (1) An exhausted 
battery; (2) lack of contact of the points in the battery switch, due 
to dirt thereon; (3) improper adjustment of the current interrupter; 
(4) broken connections; (5) failure of the contact spring of the bal- 
ancing mechanism to make contact with the bridge wire ; (6) trouble 
with the telephone. 

If on closing the battery switch the interrupter gives a buzzing 
note but no sound is received in the telephone, the trouble can not 



no 



INSTRUCTIONS TO FIELD PARTIES. 



be in the battery or interrupter. If the interrupter does not work, 
see that the switch contacts are clean; then examine the inter- 
rupter . By adjusting the screw of the interrupter it can be made 
to work if the battery is all right. If it does not work, examine the 
connections of the battery and induction coil. If these are good, 
then the battery must be replaced by a new one. Should the inter- 
rupter work satisfactorily, but no sound be heard in the telephone 
receiver, a broken circuit exists or the telephone may be out of 
order. The broken circuit can be found usually by carefully exam- 
ining the connections. If the difficulty appears to be in the bridge 
wire, the bridge-wire slide should be examined and adjusted, if 
necessary, by carefully turning the set screw. A\Tien a note is heard 
in the receiver for a part of the scale only, the trouble is with the 
bridge-wire contact. In case the fault seems to be in the receiver 
the connections inside the bridge box should be examined, and 
then the screws binding the cord terminals. If these are satisfac- 
tory, thfe receiver should be tested directly on the battery circuit. 

If the fault is not located by any of the above means, the trouble 
must be inside the coils. Under such circumstances it is unwise to 
attempt to remove the trouble by such means as are at hand in the 
field, and the bridge should be sent to a professional instrument 
maker or electrician for repair. 

Determination of carbonates, bicarbonates, and chlorides in water. — 
When water is examined by chemical methods, as described in the 
])receding pages. 50 c. c. of water should be used in making the 
titration. Calculation of results may readily be made from the 
following table: 




INSTRUCTIONS TO FIELD PARTIES. Ill 

Qualitative Determination of Alkali Salts. 

Should a further field examination of crusts, minerals, concre- 
tions, or other substances appear desirable as supplementary to the 
ordinary field tests, or as preliminary to laboratory analysis, the 
following simple methods may be used: 

Calcium. — To about 25 c. c. of the filtered soil solution add a little 
concentrated hydrochloric acid, and then enough ammonia water 
to impart a perceptible ammoniacal odor. Should a precipitate be 
formed redissolve in hydrochloric acid and again make alkaline 
with ammonia water. Repeat the alternate addition of hydro- 
chloric acid and ammonia water until no white precipitate is formed 
when the solution is alkaline with ammonia. Then add a few 
crystals of ammonium oxalate and heat to boiling. Allow to stand 
a few minutes. A white precipitate shows the presence of calcium. 
A slight turbidity indicates small amounts of calcium. 

Magnesium,. — Filter off the calcium precipitate on a small filter, 
cool the filtrate, and add a few crystals of sodium phosphate. 
Shake to dissolve the phosphate, then add ammonia water equal in 
amount to about one- third of the volume of the liquid, and let 
stand for at least one hour. A white crystalline precipitate shows 
the presence of magnesium. The precipitate is rather slow in 
appearing when the magnesium is present in small quantities, and 
may be hastened in forming by scratching the sides of the vessel 
with a glass rod, in which case the precipitate will appear first on 
the scratched places. 

Sodium and 'potassium. — Quite small quantities of these metals 
may be detected by the flame test. Clean the platinum wire by 
dipping in hydrochloric acid and heating in the colorless flame of 
the alcohol lamp until it no longer colors the flame. An ordinary 
candle or lamp flame can not be used. Then dip the lopped end 
of the wire in the soil solution or solid salt to be treated and put into 
the flame. A strong yellow color shows the presence of sodium. 
The violet color of the potassium is masked by the intense yellow 
of the sodium, and this color must, therefore, be screened out by 
looking at the flame through blue cobalt glass. The potassium, if 
present, is then recognized by the violet color of the flame. 



112 T>'STRUCTIONS TO FIELD PARTIES. 

Chlorides. — Add sufficient arid fpreferablr HKSO^> other than 
liydrochloric acid to decompose the carbonates. Add silver 
nitrate, which gives a white insoluble precipitate of silver chloride 
which is soluble on the further addition of ammonia water. The 
addition of the acid is necessary, since silver carbonate is also a 
white insoluble precipitate. 

Sulphates. — Add sufficient hydrochloric or nitric acid to decom- 
pose carbonates. Unless a decided excess of acid is added it wiU 
lie necessary to boil the solution. The addition of barium chloride 
will then precipitate insoluble white barium sulphate. 

Carbonates. — Dissolved carbonates are recognized by the red color 
imparted to the solution by phenolphthalein indicator. 

Bicarbonates. — Dissolved bicarbonates are distinguished from car- 
bonates in that they produce no reaction with phenolphthalein 
indicator, but show a yellow color with methyl orange indicator, 
which must not change to a red on the addition of one or two drops 
of the X/20 KHSO4 solution. The volume of the X/20 KHSO4 
solution used is a measure of the amount of bicarbonate as ex- 
]ilained under the quantitative method for bicarbonates. 

Xitrates. — Add some crystals of ferrous sulphate to the solution. 
Hold the test tube at a slanting angle and pour, very carefully, 
concentrated sulphuric acid against the lower sides of the tube so 
that it will run to the bottom and form with the original solution 
two liquid layers. The formation of a brown ring indicates the 
presence of nitrates. Care should be taken not to shake the tube 
or add the concentrated sulphuric acid in such a way as to allow it 
to mix quickly with the solution, for it develops great heat and 
may scatter the contents of the tube with explosive violence. 

Apparatus and reagents required. 
1 dozen large test tubes. 
1 2-iach glass funnel. 

1 package filter paper, Schleicher & Schiill's No. 595. 7 cm. 
1 alcohol lamp. 
4 inches platinum wire. 
1 square inch of blue cobalt glass. 
1 bottle concentrated hydrochloric acid. 
1 bottle concentrated ammonia. 
1 bottle concentrated sulphuric acid. 
Crystals of ammonium oxalate. 



FORM OF A SOIL SURVEY REPORT. 113 

Crystals of sodium phosphate. 
Crystals of ferrous sulphate. 
Crystals of barium chloride. 
Solution of silver nitrate. 
N/20 KHSO4 solution. 
Phenolphthalein indicator. 
Methyl orange indicator. 
Red and blue litmus paper. 

Collection of Laboratory Samples of Alkali Soils, Crusts, 
AND Waters. 

Samples of water, crusts, etc., sent to the bureau laboratories for 
chemical examination, or for the purpose of checking the accuracy 
of the bridge, should be fully noted and described in the field note 
book and accompanied by a description on Form 48. 

In collecting water for analysis three or four of the sample bottles 
protected by mailing cases should be thoroughly rinsed out and 
then filled. In collecting alkali crusts, only clean, firm sacks 
should be used, and in the case of highly concentrated sodium 
carbonate crusts two or three sacks, one within the other, should be 
used to inclose the material, because of its corrosive properties. 

FORM OF A SOIL SURVEY REPORT. 

A soil map of an area needs for its proper interpretation a report 
carrying a description of the soils, a discussion of their economic 
relations, and a statement of their agricultural possibilities, and this 
in turn requires that consideration be given to existing physical 
conditions such as climate, topography, and physiography, and loca- 
tion with respect to transportation and market facilities. 

The matter should be presented in a direct style, and no more 
words used than are absolutely necessary to convey the meaning, 
being careful, however, to treat each subject so that all important 
phases may be brought out and clearly stated . In order to attain 
this, the different chapters should be revised several times if neces- 
sary, so that all important matters may be considered and all unnec- 
essary words eliminated . A careful consideration of this matter of 
style in writing is enjoined upon all members of the bureau charged 
with the preparation of reports. The material for the report should 



FORM OF A SOIL SURVEY REPORT. 115 

The regional drainage is to be described with reference to the 
area as a whole rather than with reference to any particular 
soil type. It should be described in terms of the completeness of 
the drainage over the whole area, i. e., whether all parts of the area 
are reached by drainage ways or slopes to them or whether some 
parts of it still retain a simple constructional surface form without 
adequate provision for natural surface drainage. The depth of the 
dissection by the streams and the width of the larger valleys 
should be stated. Where the streams are small or are still so young 
that a uniform grade profile has not yet been established some 
idea of the fall should be given. 

Describe the character, source, and distribution of the popula- 
tion. The density of the rural population per square mile is 
significant. 

Name the chief towns, the principal transportation facilities and 
the important markets for the disposal of the products of the soil. 

Climate. — Put in a very brief statement of the climatic features, 
using the Weather Bureau statistics furnished by the office. Any 
observed relations between the agriculture and climate may be 
brought out, especially where conditions differ in different parts of 
the survey or where they are unusual or particularly important 
from the agricultural point of view. 

Agriculture. — This subject should begin with a brief history to 
show the length of time the soils have been under agricultural 
occupation, the changes that have taken place in the character of 
agriculture, owing to economic, social, or other causes. The object 
of this discussion is to show the different agricultural practices and 
uses to which the soils of the area have been subjected in the past. 

A careful statement should then be made covering the present 
condition of agriculture in the area. For this purpose the Census 
returns of the acreage or value of the principal crops by classes will 
serve as a guide. The influence of the soil or of topography, 
physiography, local climatic conditions or market conditions should 
be brought out in describing the local distribution of these crops in 
the area. In order to fix this matter in the mind of the soil man and 
to convey the correct impression of existing conditions to the reader 
it is sometimes advisable to prepare a small sketch map oi not 



116 INSTRUCTIONS TO FIELD PARTIES. 

exceeding a township in one or more localities in the area upon 
whicli the actual distribution of the different croi:)s or classes of 
cr()|)s as they exist at the time of the survey is shown. This will be 
found particularly advantageous in such areas as are not uniform 
but where from differences in soils, topography, physiography, or 
climatic conditions there are local segregations imposed by natural 
or artificial causes. The inspector or ofhcer in charge will indicate 
when and where the construction of such maps is advisable. 

It will be well to show in this general chapter on agi-iculture how 
much recognition is now given to the general adaptation of soils to 
classes of crops and to agricultural industries. 

The rei)ort will tlu^i discuss the agricultural methods in use, 
including the adequacy of farm equipment, the methods of culti- 
\ation, tlie rotation of crops, the ext(>nt and charact(^r of fertiliza- 
tion, and other practices in use to bring out the full measure of 
soil productivity. 

The charact(n- and (^ost of labor axailable for the handling of the 
soil should be stated. The size of farms and the tenure should be 
shown, to bring out in general the magnitude and methods of the 
unit control of the soil, and finally a statement should be made of 
the range in value and average value of farm lands. 

.S'o/V.s'. -The d('scri])ti()n of the soil types encountiM'ed in the area 
sh(;ul(l hv prec(Hled l)y a general chapter discussing the origin and 
mode of formation of the soils of the region as a whole, particularly 
with reference to that ])hase of geology that has to do with the 
lilhological character of the material. It is important that the 
geological relationship of the soils should be shown, but the name of 
a geological formation should never be given without reference to a 
geological maj) of the area or the statement of some recognized 
authority. The soil man. however, is supposed to know how to 
identify the common rocks and may name the rocks on his own 
authority if he is sure or can satisfy himself about the identification, 
but such statements should be in general terms, such as limestone, 
sandstone, sliale, slate, granite, diorite, gabbro, basalt, diabase, 
rhyolite, trachyte, gneiss, schist, and serpentine. If unable to 
identify the igneous rocks he should at least describe them as light 
or dark colored, as coarse or fine grained, as quartz-bearing or 



FORM OF A SOIL SURVi;i Kli:iuivi. 117 

quartz-free rock, as the case may be, with abundant hornblende or 
such othef mineral as they may contain.' The field man should 
keep clearly in mind that the age of a rock is of no essential value in 
soil classification but that its lithological character is of very great 
value. 

The relation of soils to the general physiographic features should 
be discussed, and formative or modifying agencies of significance 
pointed out. Then the classification and distribution of the 
soil series should be taken up, particularly with reference to the 
character of the material and the agencies which have been 
operative in its accumulation. 

In taking up the detailed description of the soil types all the types 
within a given series should be described before any other type 
under a different series, regardless of its relative importance in 
that particular area, is taken up and each series group should be 
preceded with a short description of the series, giving the color of 
soil and subsoil, texture of the soil when it is distinctly different 
from that of the subsoil, the structure of the subsoil, derivation of 
the material, the process of its accumulation and the topography. 
This should be brief. This series description is to be the typical 
series description, not a description of the series as it occurs in the 
area under discussion if it varies in that area from the typical. 

Next there will follow a detailed description of each soil type 
encountered in the area. Give first the color, texture, and depth of 
soil and subsoil, the character of any substratum observed, and 
any mineral ogical or chemical feature which is apparent.^ Fol- 
low this with a statement of the location of the soil in the area, 
the character of the surface and the drainage conditions. Include 
if necessary more detailed description of the origin and process of 
formation than that already given in the series description, but 
this will rarely be necessary. 

1 Where unable to identify or to determine the hthological character of an impor- 
tant soil-forming rock, the field man may send specimens to the laboratories for 
identification. 

2 Where areas of other soil types, because of their small size or the complexity of 
arrangement, are included with any soil this fact should be stated, and where the 
included material is of sufficient importance some space may be given to its de- 
scription. 



118 IXSTKUCTIONS TO FIFJJ) PAKTIES. 

Follow Ihis with a di.-cus.sioii of ilic ('coiioinic relation of the soil 
{y])o to the auriciilture of tlio area. Slate ap])roxiinately how 
iiiuch of tlio soil {y\H^ is actually in uso at tho })r('son(, tinip f(.r 
a,u:ricultiin'. if a consiclorahk^ ])art of I lie tyi)o is not in nsc for 
snch ol)vious ))liysical reasons as i-on^li to|)0<i:rapliy, insnilicient 
or excessive (li-aina,<>e. alkali, or other cause, discuss briefly the 
]>ossil)ility of use ilu-ough reclainaiion oi- nio(lilic(l use. Describe 
the imi)ortant crops that are beini;- ui'own on the l\pe. not a mere 
list of croj)s but a carefully wei.ulic(l statement based uj)on ol)serva- 
tion of the relati\(' importance of the ci'o})s or industries. Tables 
coni|)il(Ml from ic ports of the Census showin^i: the acreage and yields 
of all imj)oi-lant crops of the couiUy will be furnislied each field 
party on i-e(pie.s| as an aid in the preparatioTi of this material. 
.\pl)ended i.s a list of all ci-ops of the I'niled States as reported 
l>y the Census with tlieii- i-elali\c \aliies. Care must be taken ai 
all tinu's to express tlie relali\-e importance of crops in the soil 
tyjx' as a whoh- or o!i thai ponion of it which is in use. .\n ini- 
})ortant uarcUui veiiclable sl.ouM not be mentioned in such a way 
as to indicate that it is an important commercial croj) unless such 
be the case. The ob.served residt of a single individual in success- 
luUy ])roducing a crop new to the s )il ty|)e may be mentioned by 
way of suggestion. !)ut must not be use(l as a basis for a definite 
slatemenl of general aj)[)lication. In (liscu.ssing animals or anima 
l)ro(Uu'tsit will be well tostal(> not oidy thedifferentkindsof animals 
j)roduced and the importance of the business, whether commercial 
or not. but also whether the .soil i< us(m1 for range cattle or feeding 
cattle oi- both, oi- for (huryin.g. Tlie type of dairying should he 
brought out. If potatoes ai-e recogni/.ed as an im])ortant com- 
mercial crop the pei-iod of nuUurity of the crop should be given to 
indicate the market period serxcd. to show whether they will be 
a\ailable for sprin-;-. sununer. fall, or winter use. An important 
industry (h'Ncloped on a small portion of a soil type must be de- 
scrilxMl as an e\amj)le of local ii.'^e. carefully restrieting the appli- 
cation of I lie statement in the present use of the soil as a whole, 
otherwise such dkscussions may be misleading. Conservative state- 
ments shoidd l)e nuide of the yield of the principal cTops either in 



FORM or A SOIL SURVEY REPORT. 119 

average figures for the type as a whole or as yields obtained under 
average methods and under good farming methods. This is done 
to illustrate the productivity of the soil type as compared with 
other soils in the area and to suggest what may be expected by 
improving the methods. Statements concerning yields should be 
very carefully made and based on carefully obtained evidence only. 
The field man should not forget that the yields of crops depend 
upon many other factors besides the single one of the soil. 

There are three classes of data on which field men are apt to 
base statements of crop yields as follows: (1) Actual, figures gath- 
ered and sifted with care and discrimination. (2) Observation of 
the actual appearance of crops during the progress of the field 
work. (3) General impressions gained during the progress of the 
field work but rather unconsciously. In every case the field man 
should state the basis on which he makes a statenient of crop yields. 

In this chapter something should also be said of the prevailing 
methods of handling the soil and of the fertilizer practice. Land 
values, the range in price And average price, should be shown. 
These should be based on actual transfers, if possible. In all cases, 
however, the basis of any statement should be given. 

Great care must be exercised in making recommendations for pos- 
sible improvement in the form of agricultural practice, as it must be 
recognized that this depends upon other factors than soil character, 
and other bureaus are considering and actually handling questions 
of introduction of methods, crops, and industries connected with 
their work. 

Sugge Lions of this kind and statements regarding adaptations of 
the soils to crops not now grown in an important way within the 
area coming from this bureau should be tentative, and when based 
upon observations made outside of the area, so far as possible, the 
basis for these suggestions should be given and the localities, where 
the changes suggested have been in actual operation, should be 
stated. Specific reference should be made to such localities and to 
such cases in order to show that the suggestion comes from actual 
observation and to enable verification of the value of the proposed 
change by investigation of the authority or the case cited. Further- 

42126—14 6 



120 INSTRUCTIONS TO FIELD PARTIES. 

more, such a suggestion must not be made as of general application 
if it is known to be dependent upon and applicable only to local 
conditions of transportation, market demands, or other limiting 
causes, without bringing out these limiting conditions. 

Irrigation, drainage, alkali. — In cases where irrigation, drainage, 
or alkali conditions constitute a controlling factor in the use of soils, 
special chapters may be prepared on such subjects, but the subjects 
must be briefly stated and discussed only in their specific bearing 
upon the character and use of the soil. 

Summary. — Prepare a brief paragraphic resume of salient points 
brought out in the report. This should include the use of soils, 
deductions made from the study of conditions and methods of han- 
dling the soil, and suggestions for improvement or changes in the 
agricultural methods, and in the crops grown, under the limitations 
above mentioned. 



APPENDIX. 



The value of the agricultural products of the United States. 
[1910 census.] 



Value. 



Per cent. 



Cereals, 1 : 

Animals sold or slaughtered, 2 

Cotton and seed, 3 

Hay and forage, 4 

Dairj^ products sold, 5 

Fowls and eggs sold, 6 

Other vegetables, 7 

Potatoes and sweet potatoes, 8 

Forest products of farms 

Orchard fruits, 9 

Tobacco 

Other grains and seeds, 10 

Wool 

Sugar crops, 11 

Flowers and plants 

Small fruits, 12 

Tropical and semitropical fruits, 13 

Grapes 

Nursery products 

Other minor crops, 14 

Nuts, 15 



665, 539, 

833, 175, 

824,696, 

824,004, 

473,769, 

256,041, 

216,257, 

201,853, 

195,306, 

140, 867, 

104,302, 

97, 536, 

65,472, 

61,648, 

34, 872, 

29, 974, 

24, 706, 

22,027, 

21,050, 

18, 068, 

4,447, 



$8,115,620,752 



NOTES. 
I. Cereals — values: Percent. 

Com 54 

Wheat 25 

Oats 15 

Barley 3 

Rye 1 

Rough rice 1 

Kafir com and milo maize (i) 

Buckwheat (i) 

Emmer and spelt (i) 



Less than one-half of 1 per cent. 



121 



APPENDIX. 



123 



7. Other vegetables— Continued. 
Relative acreage— Con. Per cent. 



Green peppers . 
Cauliflower. . . . 

Beets : . . . 

Squash.... 

Rhubarb 

Radishes 

Kale. 

Horse-radish.. 
Pumpkins. ... 
•Eggplant...... 

Parsnips 

Rutabagas.... 

Sprouts 

Okra.... 

Parsley. 

Green onions. . 



C) 
0) 
C) 
C) 
(1) 
G) 
0) 
0) 
0) 
0) 
0) 
0) 
0) 
0) 
G) 
(0 



Relative values— Gon; 



Per cent. 



Green peppers. 

Beets 

Rhubarb 

Pop corn 

Radishes 

Horse-radish , . 

Squash... 

Eggplant. 

Kale 

Parsnips 

Sprouts 

Green onions. . 

Rutabagas 

Pumpkins 

Parsley 

Okra 



1 

1 

1 

0) 

0) 

(0 

0) 

0) 

0) 

0) 

0) 

0) 

0) 

G) 

(0 

Per cent. 



8. Potatoes and sweet potatoes— values: 

Potatoes 82 

Sweet potatoes 18 

9. Orchard fruits— values: 

Apples 58 

Peaches 20 

Plums and prunes 8 

Pears 5 

Cherries 5 

Apricots 2 

10. Other grains and seeds— values: 

Flaxseed 29 

Dry beans 22 

Peanuts 19 

Grass seed 17 

Dry peas 11 

Flower and vegetable seeds , 1 

11. Sugar crops— values: 

Sugar cane 43 

Sugar beets 32 

Sorghum cane 16 

Maple sugar and sirup 9 

12. Small fruits— values: 

Strawberries 60 

Raspberries 17 

Blackberries 13 

Cranberries 6 



Less than one-half of 1 per cent. 



124 INSTIU'CTIONS TO FIFIJ) PAKTIES. 

13. Tropical and semitropical fruits— values: Percent. 

Oranges 71 

Lemons 12 

Grapefruit 8 

Figs 3 

Pineapples 3 

O lives 2 

14. Other minor crops— values; 

Hops 43 

Broom com 28 

Not specified 26 

Hemp •. 3 

15. Nuts— values: 

English walnuts 52 

Pecans 22 

Almonds 16 

AI: others 10 

:.. o 



I 



